Question 16466
First rewrite the expression.

{{{(4x^(-1)y^(-3))(7x^2y)}}} = {{{(4/x)(1/y^3)(7x^2y)}}} = {{{(4/xy^3)7x^2y)}}} = {{{(4*7x^2y)/xy^3}}} = {{{28x/y^2}}}