[tex]\bf f(x,y)=xy-x^2 \\\\[-0.35em] ~\dotfill\\\\ f(\stackrel{x}{-2},\stackrel{y}{3})=(-2)(3)-(-2)^2\implies f(-2,3)=-6-(4)\implies f(-2,3)=-10 \\\\[-0.35em] ~\dotfill\\\\ f(~~\underline{f(-2,3)},~~-4)\implies f(\stackrel{x}{\underline{-10}},\stackrel{y}{-4})=(-10)(-4)-(-10)^2 \\\\\\ f(-10,-4)=40-(100)\implies f(-10,-4)=-60[/tex]
