`(x-1/2)+75%=9/10`
`(x-1/2)+3/4=9/10`
`x-1/2=9/10-3/4`
`x-1/2=3/20`
`x=3/20+1/2=13/20`
\(\left(x-\dfrac{1}{2}\right)+75\%=\dfrac{9}{10}\\ \left(x-\dfrac{1}{2}\right)+\dfrac{3}{4}=\dfrac{9}{10}\\ \left(x-\dfrac{1}{2}\right)=\dfrac{9}{10}-\dfrac{3}{4}\\ \left(x-\dfrac{1}{2}\right)=\dfrac{3}{20}\\ x=\dfrac{3}{20}+\dfrac{1}{2}\\ x=\dfrac{13}{20}\)