Answer:
f(x) = (x+10)^2 - 4
Step-by-step explanation:
vertex form is y = a(x-h)^2+k
to complete the square, we want to add a number on both sides so x^2+20x+whatver the number is, is the square of something
to find that number take 20, divide by 2, and then square it to get 100.
so, you would get f(x)+100 = x^2+20x+100+96
subtract 96 on both sides: x^2+20x+100 = f(x) + 4
factor: f(x) = (x+10)^2 - 4
