Given LaTeX: \int_8^{12}f\left(x\right)dx=31,\:\ :\int_8^{12}g\left(x\right)dx=-17∫ 8 12 f ( x ) d x = 31 , ∫ 8 12 g ( x ) d x = − 17 , find: LaTeX: \int_8^{12}\left[3f\left(x\right)-2 g\left(x\right)\right]dx∫ 8 12 [ 3 f ( x ) − 2 g ( x ) ] d x