Question

What is the intermediate step in the form (x + a)2 = b as a result of completing the

square for the following equation?
2x2+ 40 = -8x

Answer 1

Explanation:

Simplify this problem by dividing all three terms by 2:

x^2 + 20 = -4x

Rewrite this in standard form:

x^2 + 4x + 20

Take the coefficient of the x term and divide it by 2: 4/2 = 2

Square this result: 2^2 = 4

Between x^2 + 4x and 20 add this 4, then subtract it:

x^2 + 4x + 4 - 4

Rewrite x^2 + 4x + 4 as the square of a binomial:

(x + 2)^2 - 4, or (x + 2)^2 = 4