Question

express each equation in the form y = a(x – h)2 + k. Then identify a, h, and k.

y = x2 + 8x + 20

Answer 1

(x+4)^2+20-16

a=1
h=-4
k=4

Answer 2

Why

Answer 3

You have to complete the square, for this example as the coefficient in front of the x^2 is 1, all you do is half the find a factorised quadratic that will equal this. and then minus the constant at the end 4*4 =16 so you minus that to find k

Answer 4

half the 8x so you get 4, as when multiplying out that bracket you get x^2+4x+4x+16

Answer 5

but when you complete the square you always minus the x0 value from it in this case 16