I can't identify how line 1 has simplified to line 2 in this equation. I've been staring at this for quite a while, but nothing has come to me yet. I think it's just the numerator that is confusing me, since the denominator's powers cancel nicely. I think they have divided by 3 and multiplied by something similar to $2(5x+3)^{-1}$. I just can't see what!
Can anyone give me any hints? Many thanks!