The expression is $(4x-12)+(1/2xy-10)$. We are given that $x=4$ and $y=6$, so we can substitute these values into the expression to get $(4(4)-12)+(1/2(4)(6)-10)$. Simplifying gives $(16-12)+(12-10)$. Continuing to simplify gives $4+2$. The value of the expression is $\boxed{6}$.
