(x-1)^2-9(x+1)^2=0

2 min read Jun 17, 2024
(x-1)^2-9(x+1)^2=0

Solving the Equation: (x-1)^2 - 9(x+1)^2 = 0

This equation is a quadratic equation in disguise. Let's break it down and find the solution(s):

1. Expand the Squares

First, we need to expand the squares using the formula (a - b)^2 = a^2 - 2ab + b^2 and (a + b)^2 = a^2 + 2ab + b^2.

  • (x - 1)^2 = x^2 - 2x + 1
  • 9(x + 1)^2 = 9(x^2 + 2x + 1) = 9x^2 + 18x + 9

Now our equation becomes: x^2 - 2x + 1 - 9x^2 - 18x - 9 = 0

2. Simplify the Equation

Combining like terms, we get: -8x^2 - 20x - 8 = 0

We can simplify this equation by dividing both sides by -4: 2x^2 + 5x + 2 = 0

3. Solve the Quadratic Equation

Now we have a standard quadratic equation in the form ax^2 + bx + c = 0. We can solve this using the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / 2a

In our case, a = 2, b = 5, and c = 2. Plugging these values into the quadratic formula, we get:

x = (-5 ± √(5^2 - 4 * 2 * 2)) / (2 * 2) x = (-5 ± √9) / 4 x = (-5 ± 3) / 4

This gives us two possible solutions:

  • x = (-5 + 3) / 4 = -1/2
  • x = (-5 - 3) / 4 = -2

Conclusion

Therefore, the solutions to the equation (x-1)^2 - 9(x+1)^2 = 0 are x = -1/2 and x = -2.