Answer
$-4x^5y^3$
Work Step by Step
Cancel the coefficients' common factors and simplify the variables uising the quotient rule for exponents $(\frac{a^m}{a^n}=a^{m-n}, a\ne0)$ to obtain:
$\require{cancel}
=-\dfrac{25(4)}{25}x^{6-1}y^{8-5}
\\=-\dfrac{\cancel{25}(4)}{\cancel{25}}x^{5}y^{3}
\\=-4x^5y^3$
