$a$) `(3x + 2)^5 = 1/32`
`⇔ 3x+2 = 1/2`
`⇔ x = -1/2`
Vậy `x=-1/2`
$c$) `1/4 . 26 . 3/8 . 4/{10} ..... . {30}/{62} . {31}/{64} = 4^x`
`⇔ {1.2.3...........30.31}/{2.2.2.3.2.4.2.5.........2.31.2.31.2.32} = 4^x`
`⇔ 1/{2^36} = 4^x`
`⇔ x = -18`
Vậy `x=-18`