a/ \(\frac{-1}{5}x^3y^2\frac{5}{4}xy^3\)
\(=\left(\frac{-1}{5}.\frac{5}{4}\right)\left(x^3.x\right)\left(y^2.y^3\right)\)
\(=\frac{-1}{4}x^4y^5\)
b/ \(-3xy^4\left(-\frac{1}{3}\right)x^2y\)
\(=\left(-3.\frac{-1}{3}\right)\left(x.x^2\right)\left(y^4y\right)\)
\(=1x^3y^5\)