\(=>x=\dfrac{12}{8}-\left(\dfrac{15}{4}-3\right)=\dfrac{6}{4}-\dfrac{3}{4}=\dfrac{3}{4}\)
\(\dfrac{12}{8}-x+3=\dfrac{15}{4}\)
\(\dfrac{12}{8}-x=\dfrac{15}{4}-3\)
\(\dfrac{12}{8}-x=\dfrac{3}{4}\)
\(\dfrac{6}{4}-x=\dfrac{3}{4}\)
\(x=\dfrac{6}{4}-\dfrac{3}{4}\)
\(x=\dfrac{3}{4}\)