## Elementary Algebra

$-35x^{5}y^{5}$
We use the rule $a^{m}\times a^{n}=a^{m+n}$ in the simplification of the expression: $(-5x^{2}y)(7x^{3}y^{4})$ =$(-5\times7)\times(x^{2}\times x^{3})\times(y\times y^{4})$ =$(-35)\times(x^{2+3})\times(y^{4+1})$ =$(-35)\times(x^{5})\times(y^{5})$ =$-35x^{5}y^{5}$