(x^2-8)^2+x^2-8=20

2 min read Jun 17, 2024
(x^2-8)^2+x^2-8=20

Solving the Equation: (x^2-8)^2+x^2-8=20

This equation might look intimidating at first glance, but it can be solved using a simple substitution. Here's how:

1. Substitution

Let's make the equation easier to work with. We can substitute y = x^2 - 8. This transforms the equation into:

y^2 + y = 20

2. Rearranging and Factoring

Now we have a quadratic equation:

y^2 + y - 20 = 0

This can be factored into:

(y + 5)(y - 4) = 0

3. Solving for y

This gives us two possible solutions for y:

  • y = -5
  • y = 4

4. Back-Substituting to Find x

Now we need to substitute back our original expression for y:

  • x^2 - 8 = -5
  • x^2 - 8 = 4

Solving for x in each case:

  • x^2 = 3 => x = ±√3
  • x^2 = 12 => x = ±2√3

5. The Solutions

Therefore, the solutions to the equation (x^2-8)^2+x^2-8=20 are:

  • x = √3
  • x = -√3
  • x = 2√3
  • x = -2√3

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