Given the equation
[tex]\frac{-3}{4}-\frac{2}{3}=\frac{5}{4}u-\frac{2}{3}u[/tex]We add and subtract similar terms:
[tex]-\frac{17}{12}=\frac{7}{12}u[/tex]Multiply both sides by 12:
[tex]\begin{gathered} -\frac{17}{12}\cdot12=12\cdot\frac{7}{12}u \\ -17=7u \end{gathered}[/tex]Divide both sides by 7:
[tex]\begin{gathered} -\frac{17}{7}=\frac{7u}{7} \\ u=-\frac{17}{7} \end{gathered}[/tex]Answer:
[tex]u=-\frac{17}{7}[/tex]