To evaluate an expression with variables that the problem gives you values for, you can simply "plug in" the value for the variable in the expression.
In this instance, we are going to replace the variables [tex]r[/tex] and [tex]s[/tex] with -36 and 6, respectively. This is solved as:
[tex]\dfrac{2r}{3s}, r = -36, s = 6 \Rightarrow \dfrac{2(-36)}{3(6)} = \dfrac{-72}{18} = \boxed{-4}[/tex]
Our answer is -4.
