Question

How do you solve `3x^2 + 20x + 36 = 4` by completing the square?

Answer 1

`f(x) = 3x^2 + 20x + 32`= `3(x^2 + (20x)/3 + 32/3) = 0`

`x^2 + (20x)/3 + 100/9 - 100/9 + 32/3 = 0`

`= (x + 10/3)^2 - 4/9 = 0` ->`(x + 10/3) = +- 2/3`

`(x + 10/3) = 2/3 -> x = -10/3 + 2/3 = -8/3`

`(x + 10/3) = -2/3 -> x = -10/3 - 2/3 = -12//3 = -4`