#### Answer

(a) $\frac{1}{3}$
(b) 126
(c) 2

#### Work Step by Step

Substituting $x=-1$ and $y=-5$ in each of the three expressions,
Part (a)
$\frac{3y}{45x}=\frac{3(-5)}{45(-1)}=\frac{-15}{-45}=\frac{1}{3}$
Part (b)
$x^{2}-y^{3}=(-1)^{2}-(-5)^{3}=(1)-(-125)=1+125=126$
Part (c)
$\frac{x+y}{3x}=\frac{-1-5}{3(-1)}=\frac{-6}{-3}=2$