Questions: Find all the real solutions to the following equation. x^2 / 3+2 x^1 / 3-8=0 Choose ALL that apply. x=-6 x=64 x=-2 x=4 x=-8 x=-12

Find all the real solutions to the following equation.
x^2 / 3+2 x^1 / 3-8=0

Choose ALL that apply.
x=-6
x=64
x=-2
x=4
x=-8
x=-12
Transcript text: Find all the real solutions to the following equation. \[ x^{2 / 3}+2 x^{1 / 3}-8=0 \] Choose ALL that apply. $x=-6$ $x=64$ $x=-2$ $x=4$ $x=-8$ $x=-12$
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Solution

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Solution Steps

To solve the equation x2/3+2x1/38=0x^{2/3} + 2x^{1/3} - 8 = 0, we can perform a substitution to simplify it. Let y=x1/3y = x^{1/3}. Then the equation becomes y2+2y8=0y^2 + 2y - 8 = 0, which is a quadratic equation in terms of yy. We can solve this quadratic equation using the quadratic formula. Once we find the values of yy, we can substitute back to find the corresponding values of xx.

Step 1: Substitute and Simplify

We start with the equation

x2/3+2x1/38=0. x^{2/3} + 2x^{1/3} - 8 = 0.

To simplify, we let

y=x1/3. y = x^{1/3}.

This transforms our equation into

y2+2y8=0. y^2 + 2y - 8 = 0.

Step 2: Solve the Quadratic Equation

Next, we apply the quadratic formula

y=b±b24ac2a y = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

where a=1a = 1, b=2b = 2, and c=8c = -8. Plugging in these values, we get:

y=2±2241(8)21=2±4+322=2±362=2±62. y = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-8)}}{2 \cdot 1} = \frac{-2 \pm \sqrt{4 + 32}}{2} = \frac{-2 \pm \sqrt{36}}{2} = \frac{-2 \pm 6}{2}.

This results in two potential solutions for yy:

y1=42=2andy2=82=4. y_1 = \frac{4}{2} = 2 \quad \text{and} \quad y_2 = \frac{-8}{2} = -4.

Step 3: Back Substitute to Find xx

Now we substitute back to find xx:

  1. For y1=2y_1 = 2:

x1/3=2    x=23=8. x^{1/3} = 2 \implies x = 2^3 = 8.

  1. For y2=4y_2 = -4:

x1/3=4    x=(4)3=64. x^{1/3} = -4 \implies x = (-4)^3 = -64.

Final Answer

The real solutions to the original equation are

x=8andx=64. \boxed{x = 8} \quad \text{and} \quad \boxed{x = -64}.

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