`3/4x-1/2=2/5`
`=> 3/4x= 2/5 + 1/2`
`=> 3/4x=4/10 + 5/10`
`=> 3/4x=9/10`
`=>x=9/10 : 3/4`
`=>x= 9/10 xx 4/3`
`=>x= 36/30`
`=>x= 6/5`
`----------`
`(x-1)^4=16`
`=> (x-1)^4=2^4`
\(\Rightarrow\left[{}\begin{matrix}x-1=2\\x-1=-2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3\\x=-1\end{matrix}\right.\)