Its simple just follow the formula (x^a) / (x^b) = x^(a-b). See now x^3 / x^7 becomes x^(3-7) = x^-4 it can also be written as 1/(x^4). Now apply for y. y^7 / y^2 = y^(7-2) = y^5 Now by combining the two fractions, x^3 y^7/ x^7 y^2 = y^5 / x^4. Hope it helps.
