-\frac{1}{2}\left(3x+4\right)^'=11
Maybe you mean
-\frac{1}{2}\left(3x+4\right)=11
\(-\frac{1}{2}\left(3x+4\right)=11\\ 3x+4=-22\\ 3x=-26\\ x=-8\frac{2}{3} \)