Answer
True by Fubini's Theorem.
Work Step by Step
Fubini's Theorem states that we can switch the iterared integral order if they have constant values, allowing:
$\int_{-1}^{2} \int_{0}^{6} x^2 \sin(x-y) \, dx \, dy = \int_{0}^{6} \int_{-1}^{2} x^2 \sin(x-y) \, dy \, dx$.
