Answer
\[\int_{0}^{4}{\int_{x}^{4}{f\left( x,y \right)}dydx}\]
Work Step by Step
\[\begin{align}
& \int_{0}^{4}{\int_{0}^{y}{f\left( x,y \right)}dxdy} \\
& \int_{y=0}^{y=4}{\int_{x=0}^{x=y}{f\left( x,y \right)}dxdy} \\
& \text{From the graph the region R is given by} \\
& x\le y\le 4 \\
& 0\le x\le 4 \\
& \text{Then,} \\
& \int_{0}^{4}{\int_{x}^{4}{f\left( x,y \right)}dydx} \\
\end{align}\]
