4-2類題一
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(1) $\int_{-2}^{2}f(x)dx=\int_{-2}^{0}f(x)dx+\int_{0}^{2}f(x)dx=-3+7=4$

(2)
$\int_{2}^{0}3f(x)dx=3(-\int_{0}^{2}f(x)dx)=3(-7)=-21$

(3)
$\int_{-2}^{2}[2f(x)+5g(x)]dx=2\int_{-2}^{2}f(x)dx+5\int_{-2}^{2}g(x)dx=8+(-5)=3$