To divide exponents they have to have the same base and then you just subtract the bottom exponent from the top exponent.
7) k × 3^9
----------- =
3^5
k × 3^9-5 =
k × 3^4 =
k × 81 = 81k
8) x^4 × y^10 × 2^11
------------------------ =
y^8 × 2^7
x^4 × y^10-8 × 2^11-7 =
x^4 × y^2 × 2^4 =
x^4 × y^2 × 16=
16x^4y^2