3x^2+12x+3

Question

solve for X

 

Answer 1

Since no method is suggested, and the format that the problem is written in sets it up to be used, I am going to solve with the Completing the Square method.

3x² + 12x = 3                               Given

x² + 4x = 1                                   Divide each term by 3 (the coefficient on the x²)

x² + 4x + 4 = 1 + 4                        Add 4 to each side (the coefficient on x, divided by 2 and squared)

(x + 2)² = 5                                  Factor the left side/simplify the right side

x + 2 = +/-√5                               Take the square root of each side

x = -2 +/-√5                                 Subtract 2 from each side