Cho $I=\int\limits_{0}^{2}{f\left( x \right)dx=3.}$ Khi đó...

$J=\int\limits_{0}^{2}{\left[ 4f\left( x \right)-3 \right]dx}=\int\limits_{0}^{2}{4f\left( x \right)dx-\int\limits_{0}^{2}{3dx=}}4\int\limits_{0}^{2}{f\left( x \right)dx-\left. 3x \right|}_{0}^{2}=4.3-3\left( 2-0 \right)=6.$