By order of operations we start with simplifying the parenthesis
[tex]\begin{gathered} -\frac{1}{2}\cdot6\left(2\right) \\ \\ \text{ Next, since the remaining operation is multiplication, do the operation} \\ \text{ from left to right} \\ =-\frac{1}{2}\cdot6\cdot2 \\ =-3\cdot2 \\ =-6 \\ \text{ Therefore,} \\ -\frac{1}{2}\cdot6\left(1+1\right)=-6 \end{gathered}[/tex]