Answer
$-15x^{6}$
Work Step by Step
We are given the expression $(-5x^{2})(3x^{4})$. Before applying the product rule for exponents, we can group like terms.
$(-5x^{2})(3x^{4})=(-5\times3)(x^{2}\times x^{4})$
According to the product rule for exponents, $a^{m}\times a^{n}=a^{m+n}$.
Therefore, $(-5\times3)(x^{2}\times x^{4})=(-15)(x^{2+4})=(-15)(x^{6})=-15x^{6}$.