need help

tofushop193 SG

how come expend like that already?as in

(20^n)(5^1-n) how to become (4^n x 5^n) x (5 / 5^n)

and

4^1+n how to become 4 x 4^n

dkcx SG

4^n X 5^n = (4X5)^n = 20^n

4^(1+n) = 4^1 X 4^n = 4X4^n