Question

Solve the equation 0= x^2 + 4x– 12 by graphing.

What are the solutions?
A. X= -6, x=2
B. X= -3, x=4
C. X=3, X=4
D. X= 6, X= -2

Answer 1

The answer is -6 or 2

Explanation:

`{x}^(2) + 4x - 12 = 0 \\ 4 / 2 = 2 \\ x1 = - 2 - u \\ x2 = - 2 + u \\ x1x2 = ( - 2 - u)( - 2 + u) = - 12 \\ 4 - {u}^(2) = - 12 \\ 4 + 12 = {u}^(2) \\ 16 = {u}^(2) \\ √(16) = + \: or - \sqrt{ {u}^(2) } \\ u = + or - 4 \\`

`x1 = - 2 - 4 = - 6 \\ x2 = - 2 + 4 = 2`