solve the Laplace's equationsolve the lapalces ? ?? ??? ???? ??? ???. Please Solve it this way ond \( 7.1 A t^{3}+B t^{2}+C t \int_{0}^{\infty} e^{-5 t} \cdot\left(A t^{3}+B t^{2}+(-t) d \frac{t}{7.2} 20 \cos 0.4 t\ 1 answer