Given that f(x)=x2−15xf(x)=x2-15x and g(x)=x+15g(x)=x+15, find

Given that $f\left(x\right)=x^2-15x$ and $g\left(x\right)=x+15$, find

(a) $f+g$ 
(b) $f-g$ =
(c) $fg$ =
(d) $\frac{f}{g}$ =