For this case we must find an expression equivalent to:
[tex]x ^ 3 * y ^ {- 7}[/tex]
By definition of power properties we have to meet:
[tex]a ^ {-1} = \frac {1} {a ^ 1} = \frac {1} {a}[/tex]
Then, we can rewrite the expression as:
[tex]x ^ 3 * \frac {1} {y ^ 7} =\\\frac {x ^ 3} {y ^ 7}[/tex]
Answer:
[tex]\frac {x ^ 3} {y ^ 7}[/tex]
