Question

What is the vertex form of f(x)=x^2+24x+138

Answer 1

(x +12)^2 - 6

Explanation:

d/dx x^2 + 24x + 138 = 2x + 24

when 2x + 24 = 0, the gradient = 0

x = -12

f(-12) = -6

therefore we have (x +12)^2 - 6.

Answer 2

f(x) = x^2 + 24x + 138
f(x) = x^2 + 24x + (24/2)^2 + 138 - (24/2)^2
f(x) = (x+12)^2 - 6