since
this is a perfect square problem, the answer will be in the form (ax +
b) ^ 2. what can you tell from looking at the original equation? x^2
does not have a coefficient in front of it, so a = 1. the second term is
negative, so b must be negative. finally, the last number 100 is the
square of + or - 10, so b must be +10 or -10, but we already figured b
has to be negative, so b = -10
