Question

Determine the number that when placed in the blank area makes the statement true

Answer 1

Notice that:

$\frac{x^{25}}{y^{35}}=\frac{(x^{-5})^{-5}}{(y^{-7})^{-5}^{}}=(x^{-5}y^7)^{-5}^{}$

Therefore, the missing number is -5.