Step-by-step explanation:
step 1. (5/3)^(-5) x (5/3)^11 = (5/3)^(-5+11) = (5/3)^6
step 2. (-2/5)^7 ÷ (-2/5)^5 = (-2/5)^7 x (-2/5)^(-5) =(-2/5)^(7-5) = (-2/5)^2.