Mình giải theo cách lớp `7` nha
`x^2+x=3/4`
`⇒x^2+x-3/4=0`
`⇒x^2+3/2x-1/2x-3/4=0`
`⇒(x^2+3/2x)-(1/2x+3/4)=0`
`⇒x.(x+3/2)-1/2(x+3/2)=0`
`⇒(x-1/2).(x+3/2)=0`
\(⇒\left[ \begin{array}{l}x-\dfrac12=0\\\\x+\dfrac32=0\end{array} \right.\)
\(⇒\left[ \begin{array}{l}x=\dfrac12\\\\x=\dfrac{-3}2\end{array} \right.\)