1. simplify x^2+x-6/x^2-4 divided by x+3/2x+4

(x^2+x-6)/(x^2-4) = (x-2)(x+3) / (x-2)(x+2)

Now divide that by (x+3) / 2(x+2)
or, equivalently, multiply by 2(x+2)/(x+3)

Lots of factors cancel.