Rewrite the following expressions using just one rational exponent. Enter the numerator and denominator of the exponent. Cancel any common factors.
$(u^{\frac{3}{2}})^{\frac{2}{7}} = u^{\frac{a}{b}}$ where $a=$ and $b =$ .
$(z^{\frac{4}{7}})^{\frac{7}{6}} = z^{\frac{a}{b}}$ where $a=$ and $b =$ .
Hint: You take a power to a power by multiplying the exponents.