Evaluate the surface integral $\int\limits_\sigma\!\!\int f(x,y,z)\,dS$ where $f=x+y$ and $\sigma$ is the portion of the plane $z = 3 - 4 x - 2 y$ in the first octant. Then

$\displaystyle\int\limits_\sigma\!\!\int f(x,y,z)\,dS = \int_a^b\int_c^d F(u,v)\,du\,dv$

=

$\displaystyle\int$

$\displaystyle\int$

$du\,dv$

    =