Solving For C And D In A Radical Equation: A Step-by-Step Guide

by Andrew McMorgan 64 views

Hey math enthusiasts! Ever stumbled upon a radical equation that seemed like a puzzle? Well, today we're diving deep into one such equation and cracking it open. We're going to figure out the values of 'c' and 'd' that make the following equation true, with the conditions that x is greater than 0 and y is greater than or equal to 0:

√((x⁶ y³) / (9 x⁸)) = (5 y^c √(2 y)) / (d x)

Let's break it down step by step so you can conquer similar challenges in the future. So, buckle up, grab your thinking caps, and let’s get started!

Simplifying the Left-Hand Side (LHS)

Okay, first things first, let's tackle the left side of the equation. Our main goal here is to simplify the radical expression as much as possible. Remember, we want to make things easier for ourselves, so let's get rid of those messy roots and fractions within roots!

Step 1: Combining Terms Under the Radical

Our starting point is √((x⁶ y³) / (9 x⁸)). The initial move involves simplifying the fraction inside the square root. To do this, we'll use the properties of exponents. When dividing terms with the same base, we subtract the exponents. So, x⁶ divided by x⁸ becomes x^(6-8) which simplifies to x^(-2). Now our expression looks like this:

√((y³) / (9 x²))

Step 2: Separating the Radical

Next, we'll use the property that allows us to separate the square root of a fraction into the fraction of square roots. Basically, √(a/b) becomes √a / √b. Applying this, we get:

√y³ / √(9 x²)

Step 3: Simplifying the Numerator and Denominator

Now, let's simplify both the numerator and the denominator. For the numerator, √y³ can be rewritten as √(y² * y), which simplifies to y√y. Remember, we're looking for perfect squares within the radical to simplify. For the denominator, √(9 x²) is straightforward. √9 is 3, and √x² is |x|. However, since we're given that x > 0, we can simply write x instead of |x|. Thus, √(9 x²) simplifies to 3x. So, our expression now looks like:

y√y / (3x)

Step 4: Final Simplified Form

So, after all that simplification, the left-hand side of the equation boils down to (y√y) / (3x). We've managed to tame that initial radical expression into something much more manageable. This simplified form is crucial because now we can directly compare it with the right-hand side of the equation and figure out the values of 'c' and 'd'. Great job, guys! We've conquered the LHS!

Simplifying the Right-Hand Side (RHS)

Alright, now that we've wrestled the left-hand side into submission, it's time to turn our attention to the right-hand side (RHS) of the equation. This side, (5 y^c √(2 y)) / (d x), looks a bit more complex, but don't worry, we'll break it down piece by piece. Our goal here is to simplify this expression and make it easier to compare with the simplified LHS we just found.

Step 1: Isolating the Variables

The RHS is (5 y^c √(2 y)) / (d x). The first thing we can do is to separate out the constants and the variables to get a clearer picture of what we're dealing with. We can rewrite the expression as:

(5√2 / d) * (y^c √y / x)

Step 2: Combining the 'y' Terms

Notice that we have y raised to the power of 'c' and also a √y term. Remember that √y is the same as y^(1/2). So, we can combine these terms by adding their exponents. This is a fundamental rule of exponents: when multiplying terms with the same base, you add the exponents. Therefore, y^c * y^(1/2) becomes y^(c + 1/2). Now, our expression looks like this:

(5√2 / d) * (y^(c + 1/2) / x)

Step 3: Comparing with LHS and Determining 'c'

Now comes the crucial part: comparing the simplified RHS with the simplified LHS we found earlier, which was (y√y) / (3x). To make these two sides equal, the powers of 'y' and the coefficients of the terms must match up.

Looking at the 'y' terms, we have y^(c + 1/2) on the RHS and y√y on the LHS. We know that y√y can be written as y^(1) * y^(1/2), which simplifies to y^(3/2). So, for the powers of 'y' to match, we need:

c + 1/2 = 3/2

To solve for 'c', we subtract 1/2 from both sides:

c = 3/2 - 1/2 c = 1

So, we've found that c = 1. Awesome! One variable down, one to go.

Step 4: Determining 'd'

Now that we know the value of 'c', let's find 'd'. We need to compare the coefficients of the terms on both sides of the equation. On the LHS, the coefficient of (y√y) / x is 1/3 (since we have (y√y) / (3x)). On the RHS, the coefficient is (5√2 / d). So, for the two sides to be equal, these coefficients must be equal:

5√2 / d = 1/3

To solve for 'd', we can cross-multiply:

d = 3 * 5√2 d = 15√2

However, wait a minute! This value of 'd' doesn't match any of the options given in the problem (c=1, d=3; c=1, d=9; c=2, d=8; c=2, d=9). This suggests there might be a slight error in the original equation or the options provided. Let's backtrack and double-check our steps to make sure we haven't made any mistakes.

Step 5: Reassessing the Equation and Options

Okay, let's take a deep breath and re-examine the original equation and the given options. Sometimes, a fresh look can help us spot any overlooked details or potential errors. The original equation is:

√((x⁶ y³) / (9 x⁸)) = (5 y^c √(2 y)) / (d x)

And the options for (c, d) are:

  • c=1, d=3
  • c=1, d=9
  • c=2, d=8
  • c=2, d=9

We correctly simplified the LHS to (y√y) / (3x) and found that c = 1 by comparing the exponents of 'y'. The issue seems to be arising when we try to match the coefficients to find 'd'.

Step 6: Identifying the Discrepancy

Let’s plug c = 1 back into the RHS and see what we get:

(5 y^1 √(2 y)) / (d x) = (5√2 * y√y) / (d x)

Now, we need to equate this to the simplified LHS, which is (y√y) / (3x). So, we have:

(5√2 * y√y) / (d x) = (y√y) / (3x)

To find 'd', we can set the coefficients equal:

5√2 / d = 1/3

d = 15√2

As we saw before, this value of 'd' doesn't match any of the given options. This discrepancy suggests that there may be a typo in the original equation or the answer choices. It's a good reminder that sometimes, even in math, things aren't always as they seem!

Conclusion: Dealing with Discrepancies

So, what have we learned today, guys? We've successfully simplified a radical equation, solved for 'c', and hit a snag when trying to find 'd'. This process highlights a crucial skill in problem-solving: the ability to recognize and deal with discrepancies. In real-world scenarios, whether in math or life, things don't always go according to plan. Sometimes, there are errors in the problem itself, or we might have made a mistake along the way.

In this case, the most likely explanation is a typo in the original equation or the answer options. If we were taking a test, this would be a good time to ask the instructor for clarification. However, the important thing is that we've understood the process of simplifying and comparing the two sides of the equation. We know how to find the values of 'c' and 'd', assuming the equation is correctly stated.

Keep practicing, keep questioning, and never be afraid to dive deep into a problem! You've got this!