Question

The equation 2x^2+12x=4 is written in the form of 2(x-p)^2+q=0. what is the value of q?

Answer 1

1) Factor out the coefficient 2: 2x^2+12x=4 => 2(x^2 + 6x) = 4

2) Complete the square of x^2 + 6x: x^2 + 6x + 9 - 9. Then:

2(x^2 + 6x + 9 - 9) = 4

3) Rewrite the square as the square of a binomial:

2( [x+3]^2 - 9) = 4, or

2([x+3]^2) = 22, or

2( [x+3]^2 ) - 22 = 0

The value of q is -22.