# Math Help - Adding and sub fractions

1. ## Adding and sub fractions

$\frac{s}{2s-6}+\frac{1}{4}-\frac{3s}{4s-12}$
Okay i know that LCD is 4(s-3) but i can't see how i get the answer of $\frac{-3}{4(s-3)}$ I cannot see how I get -3 Please help me.

2. Originally Posted by Itsbaxagain
$\frac{s}{2s-6}+\frac{1}{4}-\frac{3s}{4s-12}$
Okay i know that LCD is 4(s-3) but i can't see how i get the answer of $\frac{-3}{4(s-3)}$ I cannot see how I get -3 Please help me.
$\frac{s}{2s-6}+\frac{1}{4}-\frac{3s}{4s-12} =$

$\frac{s}{2(s-3)}+\frac{1}{4}-\frac{3s}{4(s-3)} =$

$\frac{2s}{2 \cdot 2(s-3)}+\frac{1 \cdot (s-3)}{4(s-3)}-\frac{3s}{4(s-3)} = \frac{2s + s - 3 - 3s}{4(s-3)} =$

$\frac{-3}{4(s-3)}$