Question

3x^2+12x=7 Complete the square to solve

Answer 1

Explanation:

Answer 2

x = - 2 ±
`\sqrt{(19)/(3) }`

Explanation:

3x² + 12x = 7 ← factor out 3 from each term on the left side

3(x² + 4x) = 7

to complete the square

add/ subtract ( half the coefficient of the x- term)² to x² + 4x

3(x² + 2(2)x + 4 - 4) = 7

3(x + 2)² - 12 = 7 ( add 12 to both sides )

3(x + 2)² = 19 ( divide both sides by 3 )

(x + 2)² =
`(19)/(3)` ( take square root of both sides )

x + 2 = ±
`\sqrt{(19)/(3) }` ( subtract 2 from both sides )

x = - 2 ±
`\sqrt{(19)/(3) }`