Multiply Polynomials: (6x-y)(2x-y+2)

by Andrew McMorgan 37 views

Hey guys! Today we're diving deep into the awesome world of algebra, specifically tackling a question about multiplying polynomials. You know, those expressions with variables and exponents that can sometimes look a little intimidating? Well, fear not! We're going to break down how to find the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2 step-by-step, making it super clear and easy to follow. Think of it like a multiplication puzzle, and we've got all the pieces to solve it!

So, what exactly does it mean to find the product of two expressions? It simply means we need to multiply them together. In this case, we have a binomial (6xβˆ’y6x-y, which has two terms) and a trinomial (2xβˆ’y+22x-y+2, which has three terms). When multiplying polynomials, the key is to ensure that every term in the first polynomial gets multiplied by every term in the second polynomial. No term gets left out! This is often referred to as the distributive property, but on a larger scale. We'll be using a method that systematically ensures all combinations are covered, which is crucial for getting the correct answer. Remember, a small slip-up in one multiplication can throw off the entire result, so patience and attention to detail are your best friends here. We'll explore a couple of ways to visualize and perform this multiplication, so you can pick the method that clicks best for you. Let's get started on unraveling this algebraic expression and finding that product!

Understanding Polynomial Multiplication: The Foundation

Before we jump into the specifics of our problem, let's quickly recap what polynomial multiplication entails. At its core, it's an extension of the basic distributive property you learned in earlier math classes. Remember when you had to multiply a number by a sum, like 3(x+2)3(x+2)? You'd distribute the 3 to both xx and 22, resulting in 3x+63x + 6. Polynomial multiplication works on the same principle, but with more terms involved. When we have (a+b)(c+d)(a+b)(c+d), we distribute aa to both cc and dd, and then we distribute bb to both cc and dd, giving us ac+ad+bc+bdac + ad + bc + bd. This method is sometimes called FOIL (First, Outer, Inner, Last) when dealing specifically with two binomials, but the principle extends to any combination of polynomials.

Our task is to find the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2. This means we need to multiply each term in the first expression, (6xβˆ’y)(6x-y), by each term in the second expression, (2xβˆ’y+2)(2x-y+2). The first expression has two terms: 6x6x and βˆ’y-y. The second expression has three terms: 2x2x, βˆ’y-y, and 22. So, we'll be performing a total of 2imes3=62 imes 3 = 6 individual multiplications. It’s important to be meticulous here and keep track of the signs of each term. A common pitfall is misplacing or forgetting a negative sign, so double-checking each step is vital. We are essentially distributing the entire first binomial across the trinomial. Think of it as (6x)(6x) times (2xβˆ’y+2)(2x-y+2) AND (βˆ’y)(-y) times (2xβˆ’y+2)(2x-y+2). Once we've completed these multiplications, we'll combine any like terms to simplify the final expression. This process of combining like terms is the final step in simplifying any polynomial expression after multiplication.

This foundational understanding is key. Whether you're dealing with simple binomials or more complex polynomials, the strategy remains the same: distribute every term from the first polynomial to every term in the second, and then simplify. We'll be using this exact logic to solve our specific problem. So, let's roll up our sleeves and get ready to multiply!

Step-by-Step Calculation: Finding the Product

Alright, let's get down to business and calculate the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2. We’ll use the distributive property systematically. Remember, we need to multiply each term in (6xβˆ’y)(6x-y) by each term in (2xβˆ’y+2)(2x-y+2). Let’s break it down:

First, we distribute the 6x6x from the first binomial to each term in the second trinomial:

  1. 6ximes2x=12x26x imes 2x = 12x^2
  2. 6ximes(βˆ’y)=βˆ’6xy6x imes (-y) = -6xy
  3. 6ximes2=12x6x imes 2 = 12x

So far, we have 12x2βˆ’6xy+12x12x^2 - 6xy + 12x. Now, we need to distribute the second term of the first binomial, which is βˆ’y-y, to each term in the second trinomial:

  1. βˆ’yimes2x=βˆ’2xy-y imes 2x = -2xy
  2. βˆ’yimes(βˆ’y)=+y2-y imes (-y) = +y^2
  3. βˆ’yimes2=βˆ’2y-y imes 2 = -2y

Combining these results, we get βˆ’2xy+y2βˆ’2y-2xy + y^2 - 2y.

Now, we put all the results from both distributions together:

(12x2βˆ’6xy+12x)+(βˆ’2xy+y2βˆ’2y)(12x^2 - 6xy + 12x) + (-2xy + y^2 - 2y)

This gives us the expression: 12x2βˆ’6xy+12xβˆ’2xy+y2βˆ’2y12x^2 - 6xy + 12x - 2xy + y^2 - 2y. The next crucial step is to combine any like terms. Like terms are terms that have the exact same variables raised to the exact same powers. In our expression, the like terms are βˆ’6xy-6xy and βˆ’2xy-2xy. Let’s combine them:

βˆ’6xyβˆ’2xy=βˆ’8xy-6xy - 2xy = -8xy

Now, let's rewrite the entire expression with the combined like terms:

12x2+(βˆ’8xy)+12x+y2βˆ’2y12x^2 + (-8xy) + 12x + y^2 - 2y

Which simplifies to:

12x2βˆ’8xy+12x+y2βˆ’2y12x^2 - 8xy + 12x + y^2 - 2y

This final expression represents the complete product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2. It's essential to have performed each multiplication correctly and then to have accurately combined the like terms. If you've followed along, you should see that this matches one of the answer choices provided. We'll confirm this in the next section.

Using the Box Method for Visual Learners

For those who prefer a more visual approach, the box method (also known as the grid method) can be incredibly helpful when multiplying polynomials. It ensures you don't miss any term combinations. Let’s apply it to find the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2.

We create a grid. The number of rows corresponds to the number of terms in the first polynomial, and the number of columns corresponds to the number of terms in the second polynomial. So, we'll need a 2x3 grid.

2x2x βˆ’y-y +2+2
6x6x
βˆ’y-y

Now, we fill in each box by multiplying the term in its row with the term in its column:

  • Top-left box: (6x)imes(2x)=12x2(6x) imes (2x) = 12x^2
  • Top-middle box: (6x)imes(βˆ’y)=βˆ’6xy(6x) imes (-y) = -6xy
  • Top-right box: (6x)imes(2)=12x(6x) imes (2) = 12x
  • Bottom-left box: (βˆ’y)imes(2x)=βˆ’2xy(-y) imes (2x) = -2xy
  • Bottom-middle box: (βˆ’y)imes(βˆ’y)=y2(-y) imes (-y) = y^2
  • Bottom-right box: (βˆ’y)imes(2)=βˆ’2y(-y) imes (2) = -2y

Let's update our grid:

2x2x βˆ’y-y +2+2
6x6x 12x212x^2 βˆ’6xy-6xy 12x12x
βˆ’y-y βˆ’2xy-2xy y2y^2 βˆ’2y-2y

The final step is to sum up all the terms inside the boxes:

12x2+(βˆ’6xy)+12x+(βˆ’2xy)+y2+(βˆ’2y)12x^2 + (-6xy) + 12x + (-2xy) + y^2 + (-2y)

This gives us: 12x2βˆ’6xy+12xβˆ’2xy+y2βˆ’2y12x^2 - 6xy + 12x - 2xy + y^2 - 2y. Just like with the distributive method, we now need to combine like terms. The like terms here are βˆ’6xy-6xy and βˆ’2xy-2xy. Combining them gives us βˆ’8xy-8xy.

So, the simplified expression is: 12x2βˆ’8xy+12x+y2βˆ’2y12x^2 - 8xy + 12x + y^2 - 2y.

Both methods, the distributive property and the box method, yield the same result. The box method is particularly useful for preventing errors by providing a structured way to organize all the required multiplications. It clearly lays out every component needed for the final sum. Remember, guys, consistency in applying either method is key to mastering polynomial multiplication. Keep practicing, and you'll be multiplying like a pro in no time!

Verifying the Result and Choosing the Correct Option

Now that we've meticulously calculated the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2 using two different methods, let's review our final answer and compare it to the provided options. Our calculated product is 12x2βˆ’8xy+12x+y2βˆ’2y12x^2 - 8xy + 12x + y^2 - 2y. This expression contains terms with x2x^2, xyxy, xx, y2y^2, and yy. It's important that all these terms, with their correct coefficients and signs, appear in the final answer if they are present after simplification.

Let’s look at the options given:

A. 8x2βˆ’4xy+12x+y2βˆ’2y8 x^2-4 x y+12 x+y^2-2 y B. 12x2βˆ’8xy+12x+y2βˆ’2y12 x^2-8 x y+12 x+y^2-2 y C. 8x2+4xy+4x+y2βˆ’2y8 x^2+4 x y+4 x+y^2-2 y D. 12x2+8xy+4x+y2+2y12 x^2+8 x y+4 x+y^2+2 y

By directly comparing our result, 12x2βˆ’8xy+12x+y2βˆ’2y12x^2 - 8xy + 12x + y^2 - 2y, with the options, we can see that Option B is an exact match. The coefficients and signs for all terms align perfectly with our calculation.

Let’s quickly analyze why the other options might be incorrect. Option A has 8x28x^2 and βˆ’4xy-4xy, which deviate from our calculated 12x212x^2 and βˆ’8xy-8xy. Option C also has incorrect coefficients for the x2x^2, xyxy, and xx terms. Option D has incorrect signs for the xyxy and yy terms, as well as an incorrect coefficient for the xx term. These discrepancies highlight the importance of careful calculation and attention to detail, especially with signs and coefficients, during polynomial multiplication.

Sometimes, especially in multiple-choice questions, if you're pressed for time or unsure, you might consider plugging in simple values for xx and yy (like x=1,y=1x=1, y=1 or x=2,y=1x=2, y=1) into the original expressions and then into each answer choice to see which one matches. For example, let x=1x=1 and y=1y=1. The first expression (6xβˆ’y)(6x-y) becomes (6(1)βˆ’1)=5(6(1)-1) = 5. The second expression (2xβˆ’y+2)(2x-y+2) becomes (2(1)βˆ’1+2)=3(2(1)-1+2) = 3. The product should be 5imes3=155 imes 3 = 15. Let's check Option B: 12(1)2βˆ’8(1)(1)+12(1)+(1)2βˆ’2(1)=12βˆ’8+12+1βˆ’2=4+12+1βˆ’2=16+1βˆ’2=17βˆ’2=1512(1)^2 - 8(1)(1) + 12(1) + (1)^2 - 2(1) = 12 - 8 + 12 + 1 - 2 = 4 + 12 + 1 - 2 = 16 + 1 - 2 = 17 - 2 = 15. It matches! This is a great way to quickly verify your answer or narrow down choices, but it doesn't replace the need to understand the algebraic process itself.

Understanding the process is paramount. The algebraic steps ensure accuracy for all possible values of xx and yy, whereas plugging in specific values is a verification tool. We've confirmed through detailed calculation and verification that Option B is indeed the correct product. So, when faced with such problems, remember to distribute carefully, combine like terms accurately, and check your work. That's how you conquer polynomial multiplication, guys!

Conclusion: Mastering Polynomial Products

So there you have it, folks! We've successfully tackled the challenge of finding the product of 6xβˆ’y6x-y and 2xβˆ’y+22x-y+2. By applying the distributive property systematically, or by using the visual aid of the box method, we arrived at the simplified expression 12x2βˆ’8xy+12x+y2βˆ’2y12x^2 - 8xy + 12x + y^2 - 2y. This process, while requiring attention to detail, is a fundamental skill in algebra. Each term in the first polynomial must be multiplied by each term in the second, followed by the crucial step of combining any like terms to present the answer in its most simplified form. We also discussed how to use simple value substitution as a quick check, a handy trick for multiple-choice scenarios.

Remember, mastering polynomial multiplication isn't just about memorizing steps; it's about understanding the underlying principles of distribution and simplification. The more you practice, the more intuitive these operations become. You'll start to recognize patterns and potential pitfalls, making your calculations faster and more accurate. Don't get discouraged if you make mistakes along the way – everyone does! The key is to learn from them. Go back, review your steps, and figure out where you might have missed a sign or made an arithmetic error. This iterative process is what builds true understanding and confidence.

Whether you're prepping for exams, working on homework, or just expanding your mathematical toolkit, the ability to multiply polynomials accurately is incredibly valuable. It's a building block for more advanced algebraic concepts like factoring, solving quadratic equations, and working with rational expressions. So, keep practicing these problems, and you'll be well on your way to algebraic mastery. Keep that curious mathematical spirit alive, and happy calculating!