(x+7)(x-7)=-3x

2 min read Jun 17, 2024
(x+7)(x-7)=-3x

Solving the Equation: (x+7)(x-7) = -3x

This equation involves expanding the left-hand side and then solving the resulting quadratic equation. Here's how we can break down the process:

Expanding the Equation

First, we expand the left side of the equation by applying the distributive property (or FOIL method):

(x + 7)(x - 7) = -3x

  • (x * x) + (x * -7) + (7 * x) + (7 * -7) = -3x
  • x² - 7x + 7x - 49 = -3x

Now, simplify the equation by combining like terms:

  • x² - 49 = -3x

Rearranging and Solving

To solve this quadratic equation, we need to set it equal to zero:

  • x² + 3x - 49 = 0

This equation can be solved using the quadratic formula:

  • x = (-b ± √(b² - 4ac)) / 2a

Where 'a', 'b', and 'c' are the coefficients of the quadratic equation (a = 1, b = 3, c = -49).

Substitute the values into the quadratic formula:

  • x = (-3 ± √(3² - 4 * 1 * -49)) / (2 * 1)
  • x = (-3 ± √(205)) / 2
  • x = (-3 ± √205) / 2

Therefore, the solutions to the equation are:

  • x = (-3 + √205) / 2
  • x = (-3 - √205) / 2

Conclusion

We have successfully solved the equation (x+7)(x-7) = -3x by expanding the left side, rearranging it into a standard quadratic form, and then applying the quadratic formula. The solutions to this equation are x = (-3 + √205) / 2 and x = (-3 - √205) / 2.