This problem is based on Example #1 in §12.3 of Stewart (pg 846).
The goal is to evaluate D(7x+4y)dA\displaystyle \int\int_{{D}}{\left({7}{x}+{4}{y}\right)}{d}{A}, where D\displaystyle {D} is the region bounded by the parabolas y=3x2\displaystyle {y}={3}{x}^{{2}} and y=8+x2\displaystyle {y}={8}+{x}^{{2}}.

Against which variable will you integrate first, i.e., what is the dummy variable for the inner-integral?


What are the bounds of integration for the inner integral?
lower bound =  
upper bound =  

What are the bounds of integration for the outer integral?
lower bound =
upper bound =

Work the first (inner) integral. This should result in an integral of the form abg(z)dz\displaystyle {\int_{{a}}^{{b}}}{g{{\left({z}\right)}}}{\left.{d}{z}\right.}, where z\displaystyle {z} is the appropriate variable (x\displaystyle {x} or y\displaystyle {y}). What is the function in this integrand?
the integrand is  
Hint: Look at the penultimate line in the calculation for this example.

Finally, D(7x+4y)dA=\displaystyle \int\int_{{D}}{\left({7}{x}+{4}{y}\right)}{d}{A}=