Answer
$60x^{4}y^{4}$
Work Step by Step
Since all terms are multiplied by each other, we can collect constants and variables separately in their own parentheses. We then use the rule $a^{m}\times a^{n}=a^{m+n}$ to simplify the expression:
$(-3xy)(-4y^{2})(5x^{3}y)$
=$(-3xy)\times(-4y^{2})\times(5x^{3}y)$
=$(-3\times-4\times5)\times(x\times x^{3})\times(y \times y^{2} \times y)$
=$(60)\times(x^{3+1})\times(y^{1+2+1})$
=$(60)\times(x^{4})\times(y^{4})$
=$60x^{4}y^{4}$
