Evaluate the Double Integral $\iint _ { R } ( 1 + 2 x + 8 y ) d A$

Short Answer

Evaluate the double integral $\iint _ { R } ( 1 + 2 x + 8 y ) d A$ , where $R = \{ ( x , y ) \mid 0 \leq y \leq 1 , y \leq x \leq 3 y \} .$