$$(\frac{x^{a}}{xb})\frac{1}{ab}.(\frac{xb}{x^{c}})\frac{1}{be}.(\frac{x^{c}}{x^{a}})\frac{1}{ca}=1$$
$\frac{x^{a-1}}{ab^{2}}$
$\frac{\left(a-1\right)x^{a-2}}{ab^{2}}$
