then find what 2 numbers multiply to get 100 and add to get 20
the numbers are 10 and 10
so split the center term up 100x^2+10x+10x+1 group (100x^2+10x)+(10x+1) undistribute (10x)(10x+1)+(1)(10x+1) undistribute/reverse distributive property (10x+1)(10x+1) (10x+1)^2
<span>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 </span>
