Bài 4:

a) `7^12 . 27^4 = 7^12 . (3^3)^4 = 7^12 . 3^12 = (7.3)^12 = 21^12`

b) `15^9 : 125^3 = 15^9 : (5^3)^3 = 15^9 : 5^9 = (15:5)^9 = 3^9`

c) `(0,125)^8 . 64^4 = (0,125)^8 . (8^2)^4 = (0,125)^8 . 8^8 = (0,125 . 8)^8 = 1^8`

Bài 5:

a) `4^9 . 5^27 = 4^9 . (5^3)^9 = 4^9 . 125^9 = (4.125)^9 = 600^9`

b) `3^12 . 2^16 = (3^3)^4 . (2^4)^4 = 27^4 . 16^4 = (27.16)^4 = 432^4`

Bài 6:

a) `(-5/4)^2 : (-35/24)^2 = (5/4)^2 : (35/24)^2 = (5/4 : 35/24)^2 = (5/4 . 24/35)^2 = (6/7)^2 = 36/49`

b) `(-1/2)^2 . (2/5)^2 = (-1/2 . 2/5)^2 = (-1/5)^2 = 1/25`

c) `(1/9)^2 : (1/3)^3 = ((1/3)^2)^3 : (1/3)^3 = (1/3)^6 : (1/3)^3 = (1/3)^3 = 1/27`

d) `(-1/2)^3 . (3/2)^3 = (-1/2 . 3/2)^3 = (-3/4)^3 = -27/64`