Respuesta :

The answer is 3(x+2)^2-21

Answer:

(x + 2)² = 7

Step-by-step explanation:

We have to complete the square in the given equation

3x² + 12x = 9

3x² + 12x - 9 = 0

3[x² + 4x -3] = 0

3[x² + 2(2x) + 4 - 4 - 3] = 0

3[x² + 2(2x) + 4] - 3 × 7 = 0

3[x² + 2]² - 21 = 0

(x + 2)² = [tex]\frac{21}{3}[/tex] = 7

Therefore, the square form of the equation is (x + 2)² = 7