# Math Help - Help qith solving question

1. ## Help qith solving question

(2-10 √(1÷25+h))/(h√(1÷25+h))x(2+10√(1÷25+h))/(2+10√(1÷25+h))

need to know how the numerator equals -100h. I tried it but i couldn't see how it happens!

2. Originally Posted by instantaneo
(2-10 √(1÷25+h))/(h√(1÷25+h))x(2+10√(1÷25+h))/(2+10√(1÷25+h))

need to know how the numerator equals -100h. I tried it but i couldn't see how it happens!
Spoiler:
$(a-b)(a+b) = a^2-b^2$

3. thanks!