Question

How do you solve `3x^2 + 11x – 20 = 0` by completing the square?

Answer 1

Solve y = 3x^2 + 11x - 20 = 0

Explanation:

y = 3(x^2 + 11x/3) - 20/3 = 0
(x^2 + 11x/3 + 121/36) - 121/36 = 20/3
(x + 11/6)^2 = 20/3 + 121/36 = 361/36
(x + 11/6)^2 = 361/36 =
`(x + 11/6) = +-19/6`

`x = - 11/6 + 19/6 = 8/6 = 4/3`

`x = - 11/6 - 19/6 =- 30/6 = - 5`