Solving The Radical Equation Sqrt(3x-8) + Sqrt(2x+1) + 1 = 0

by ADMIN 61 views
Iklan Headers

Hey guys! Today, we're diving deep into the fascinating world of radical equations. Specifically, we're going to tackle the equation 3xβˆ’8+2x+1+1=0\sqrt{3x-8} + \sqrt{2x+1} + 1 = 0. Radical equations can sometimes seem intimidating, but with a systematic approach and a bit of algebraic finesse, we can conquer them. This guide will walk you through the step-by-step process of solving this equation, highlighting key concepts and potential pitfalls along the way. So, grab your thinking caps, and let's get started!

Understanding the Challenge: Isolating the Radicals

The first hurdle we face with this equation is the presence of two square root terms. To effectively deal with these, our initial strategy revolves around isolating one of the radicals. Isolating a radical means getting a square root term by itself on one side of the equation. This is crucial because it allows us to eliminate the square root by squaring both sides. However, in this particular equation, we encounter a slight twist: the constant term '+1'.

So, let's start by rearranging the equation to isolate one of the square roots. We can subtract 2x+1\sqrt{2x+1} and 1 from both sides, giving us:

3xβˆ’8=βˆ’2x+1βˆ’1\sqrt{3x-8} = - \sqrt{2x+1} - 1

Now, we have successfully isolated the first square root term. This sets the stage for our next move, which involves squaring both sides of the equation. Remember, the goal here is to eliminate the square root and transform the equation into a more manageable form, ideally a polynomial equation that we can solve using standard algebraic techniques. However, it's essential to exercise caution when squaring both sides, as this operation can sometimes introduce extraneous solutions, which we'll discuss later.

Squaring Both Sides: A Critical Step

Now that we've isolated 3xβˆ’8\sqrt{3x-8}, let's square both sides of the equation. Squaring both sides is a fundamental technique for eliminating square roots in equations, but it's vital to do it carefully and with an understanding of the potential consequences. When we square both sides, we're essentially applying the operation (β‹…)2(\cdot)^2 to both the left-hand side (LHS) and the right-hand side (RHS) of the equation. This step is crucial in transforming the equation into a form that's easier to solve, but it also introduces a critical caveat: the possibility of extraneous solutions.

So, let's proceed with squaring both sides:

(3xβˆ’8)2=(βˆ’2x+1βˆ’1)2(\sqrt{3x-8})^2 = (- \sqrt{2x+1} - 1)^2

On the left-hand side, the square root and the square cancel each other out, leaving us with:

3xβˆ’83x - 8

The right-hand side, however, requires a bit more attention. We have a binomial squared, so we need to apply the formula (a+b)2=a2+2ab+b2(a + b)^2 = a^2 + 2ab + b^2. In our case, a=βˆ’2x+1a = -\sqrt{2x+1} and b=βˆ’1b = -1. Applying the formula, we get:

(βˆ’2x+1βˆ’1)2=(βˆ’2x+1)2+2(βˆ’2x+1)(βˆ’1)+(βˆ’1)2(- \sqrt{2x+1} - 1)^2 = (-\sqrt{2x+1})^2 + 2(-\sqrt{2x+1})(-1) + (-1)^2

Simplifying this, we get:

(2x+1)+22x+1+1(2x + 1) + 2\sqrt{2x+1} + 1

Thus, our equation now looks like this:

3xβˆ’8=2x+1+22x+1+13x - 8 = 2x + 1 + 2\sqrt{2x+1} + 1

This equation is a significant step forward, as we've eliminated one square root. However, we still have a square root term remaining, so we'll need to repeat the isolation and squaring process. But before we do that, let's simplify the equation further to make our next steps easier.

Simplifying and Isolating Again: The Iterative Process

Before we proceed with squaring again, let's simplify the equation we obtained in the previous step. We have:

3xβˆ’8=2x+1+22x+1+13x - 8 = 2x + 1 + 2\sqrt{2x+1} + 1

Combining like terms on the right-hand side, we get:

3xβˆ’8=2x+2+22x+13x - 8 = 2x + 2 + 2\sqrt{2x+1}

Now, let's isolate the remaining square root term. To do this, we'll subtract 2x2x and 2 from both sides of the equation:

3xβˆ’8βˆ’2xβˆ’2=22x+13x - 8 - 2x - 2 = 2\sqrt{2x+1}

This simplifies to:

xβˆ’10=22x+1x - 10 = 2\sqrt{2x+1}

We've successfully isolated the remaining square root term. Now we're ready to square both sides again. This step is crucial to eliminate the final square root and transform the equation into a polynomial form that we can solve using standard algebraic techniques. However, as before, we must remain vigilant about the possibility of introducing extraneous solutions.

Squaring Again and Solving the Quadratic: The Final Stretch

Having isolated the square root term, we're now ready for the final showdown with the radicals. Let's square both sides of the equation:

(xβˆ’10)2=(22x+1)2(x - 10)^2 = (2\sqrt{2x+1})^2

Expanding the left-hand side, we use the formula (aβˆ’b)2=a2βˆ’2ab+b2(a - b)^2 = a^2 - 2ab + b^2:

x2βˆ’20x+100x^2 - 20x + 100

On the right-hand side, we square both the constant and the square root:

(22x+1)2=4(2x+1)(2\sqrt{2x+1})^2 = 4(2x + 1)

Which simplifies to:

8x+48x + 4

Now our equation looks like this:

x2βˆ’20x+100=8x+4x^2 - 20x + 100 = 8x + 4

This is a quadratic equation, which we can solve by rearranging it into the standard form ax2+bx+c=0ax^2 + bx + c = 0. Subtracting 8x8x and 4 from both sides, we get:

x2βˆ’20x+100βˆ’8xβˆ’4=0x^2 - 20x + 100 - 8x - 4 = 0

Combining like terms:

x2βˆ’28x+96=0x^2 - 28x + 96 = 0

Now we need to solve this quadratic equation. There are several methods we can use, such as factoring, completing the square, or using the quadratic formula. In this case, let's try factoring. We're looking for two numbers that multiply to 96 and add up to -28. Those numbers are -4 and -24. So, we can factor the quadratic as:

(xβˆ’4)(xβˆ’24)=0(x - 4)(x - 24) = 0

Setting each factor equal to zero, we get two potential solutions:

xβˆ’4=0x - 4 = 0 or xβˆ’24=0x - 24 = 0

Solving for xx, we find:

x=4x = 4 or x=24x = 24

These are our potential solutions. However, we're not quite done yet. We need to check these solutions in the original equation to make sure they are valid and not extraneous.

Checking for Extraneous Solutions: The Crucial Verification Step

We've arrived at two potential solutions: x=4x = 4 and x=24x = 24. But before we declare victory, we must perform a critical step: checking for extraneous solutions. Extraneous solutions are values that satisfy the transformed equation (in our case, the quadratic equation) but do not satisfy the original radical equation. They arise because squaring both sides of an equation can introduce solutions that weren't there initially.

To check for extraneous solutions, we'll substitute each potential solution back into the original equation:

3xβˆ’8+2x+1+1=0\sqrt{3x-8} + \sqrt{2x+1} + 1 = 0

Let's start with x=4x = 4:

3(4)βˆ’8+2(4)+1+1=0\sqrt{3(4)-8} + \sqrt{2(4)+1} + 1 = 0

Simplifying:

12βˆ’8+8+1+1=0\sqrt{12-8} + \sqrt{8+1} + 1 = 0

4+9+1=0\sqrt{4} + \sqrt{9} + 1 = 0

2+3+1=02 + 3 + 1 = 0

6=06 = 0

This is clearly false. Therefore, x=4x = 4 is an extraneous solution and not a valid solution to the original equation.

Now let's check x=24x = 24:

3(24)βˆ’8+2(24)+1+1=0\sqrt{3(24)-8} + \sqrt{2(24)+1} + 1 = 0

Simplifying:

72βˆ’8+48+1+1=0\sqrt{72-8} + \sqrt{48+1} + 1 = 0

64+49+1=0\sqrt{64} + \sqrt{49} + 1 = 0

8+7+1=08 + 7 + 1 = 0

16=016 = 0

This is also false. Therefore, x=24x = 24 is also an extraneous solution.

The Verdict: No Real Solutions Exist

After meticulously solving the equation and rigorously checking our potential solutions, we've arrived at a somewhat surprising conclusion: neither x=4x = 4 nor x=24x = 24 satisfies the original equation. Both values turned out to be extraneous solutions. So, what does this mean?

It means that the original equation, 3xβˆ’8+2x+1+1=0\sqrt{3x-8} + \sqrt{2x+1} + 1 = 0, has no real solutions. There is no real number value for xx that will make this equation true.

This outcome highlights an important lesson in solving radical equations: always, always, always check your solutions. Squaring both sides of an equation is a powerful technique, but it can introduce extraneous solutions. By verifying our potential solutions in the original equation, we can weed out these extraneous values and arrive at the correct answer.

In this case, the correct answer is that there are no real solutions. Sometimes, the absence of a solution is the solution itself!

So, there you have it, guys! We've successfully navigated the twists and turns of this radical equation. Remember, the key is to isolate the radicals, square both sides (carefully!), solve the resulting equation, and, most importantly, check for extraneous solutions. Keep practicing, and you'll become a master of radical equations in no time!