Answer
$\dfrac{x^{4}-10x^{3}}{x^{2}-17x+70}=\dfrac{x^{3}}{x-7}$
Work Step by Step
$\dfrac{x^{4}-10x^{3}}{x^{2}-17x+70}$
Take out common factor $x^{3}$ in the numerator:
$\dfrac{x^{4}-10x^{3}}{x^{2}-17x+70}=\dfrac{x^{3}(x-10)}{x^{2}-17x+70}=...$
Factor the denominator and simplify:
$...=\dfrac{x^{3}(x-10)}{(x-7)(x-10)}=\dfrac{x^{3}}{x-7}$