Answer
$\dfrac{4x}{2x-1}; x \ne 0, \frac{1}{2}$
Work Step by Step
Factor the numerator and the denominator completely to obtain:
$=\dfrac{6x(4x)}{6x(2x-1)}$
Cancel the common factors to obtain:
$\require{cancel}
\\=\dfrac{\cancel{6x}(4x)}{\cancel{6x}(2x-1)}
\\=\dfrac{4x}{2x-1}; x \ne 0, \frac{1}{2}$
($x$ cannot be $0$ and $\dfrac{1}{2}$ because they will make the original expression undefined.)
