What value completes the square for the expression x^2-16x?

Question

a.-64
b.64
c.32
d.-32

Answer 1

for x^2 + bx + ....

take 1/2 of the coefficient of the x term, in your case
1/2 of 16 is 8
now square that , in your case 8^2 = 64

so you would add 16 to make it into a perfect square

test:
x^2 - 16x + 64
= (x-8)^2

yup, it works.