Suppose $R$ is the triangle with vertices $(-1, 0), (0,1),$ and $(1,0)$.

(a) As an iterated integral, $\displaystyle \iint\limits_R (3 x + 6 y)^2 \, dA = \int_A^B \!\! \int_C^D (3 x + 6 y)^2 \, dx \, dy$ with limits of integration

A =
B =
C =
D =

(b) Evaluate the integral in part (a). Hint: substitution may make the integral easier.
Integral =