Question

What number is used to complete the square for the equation x^2 = 20x?

a) 100
b) 10
c) -10
d) -100


a

Answer 1

Yes again.
x^2 -10x + 100 = 100
(x -10)^2 = 100
x -10 = +/- 10
x = 0 or 20
The same answer could have been obtained by factoring
x(x-20) = 0

Answer 2

no, when you plug 100 in to check, you get 10,000=2,000...plug in the other numbers and try them