Bài làm:
Bài 1: a) `(-3/4)^3=(-3)^3/4^3=(-27)/64`
b) `(3/5-2/3)^2=((-1)/15)^2=(-1)^2/15^2=1/225`
Bài 2:
a) `(3x+1)^3=-8`
`<=>(3x+1)^3=(-2)^3`
`<=>3x+1=-2`
`<=>3x=-3`
`<=>x=-1`
Vậy `x=-1`
b) `(2x-3)^4=81`
`<=>(2x-3)^4=3^4`
`<=>2x-3=3`
`<=>2x=6`
`<=>x=3`
Vậy `x=3`
c) `3.5^(x+1)=75`
`<=>5^(x+1)=25`
`<=>5^(x+1)=5^2`
`<=>x+1=2`
`<=>x=1`
Vậy `x=1`