1.)
x^2-3x-18/15x+45 divided by 12x/x^2-36
2.)
add and simplyfiy
2/3n^2 + 5/2n
Did you try to simplify this?
$\displaystyle \frac{(x-6)(x+3)}{15(x+3)}\cdot\frac{12x}{(x+6)(x-6)}=\frac{3(4x)(x+3)(x-6)}{3(5)(x+3)(x+6)(x-6)}=\dots$
Just cancel out the terms that bot the numerator and denominator have in common. The answer will become pretty obvious...
--Chris