Chapter 14 - Multiple Integrals - 14.1 Double Integrals - Exercises Set 14.1 - Page 1007: 8

$$\int_{4}^{6} \int_{-3}^{7} d y d x=20 $$

Given $$\int_{4}^{6} \int_{-3}^{7} d y d x $$ So, we have \begin{align} I&=\int_{4}^{6} \int_{-3}^{7} d y d x\\ &=\int_{4}^{6} d x \int_{-3}^{7} d y\\ &=[x]_{4}^{6}[y]_{-3}^{7}\\ &=(6-4)(7-(-3))\\ &=2(10)\\ &=20 \end{align}