Answer
$24$
Work Step by Step
Re-arrange the given integral as follows:
$\int_{1}^{2}[(2x) \int_{0}^{4} y dy ]dx=\int_{1}^{2}[(2x) (\dfrac{(4)^2}{0}-0) dx$
This implies that
$\int_{1}^{2} 16 x dx= 8(2^2-1^2)$
Thus, we have, $32-8=24$