Question

Complete the square to solve 3x^2+12x=9

Answer 1

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

Answer 2

(x + 2)² = 7

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 =
`(21)/(3)` = 7

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