Answer
$$ 2.4 e^{x}-\frac{7}{\ln 3}\left(3^{x}\right) +c$$
Work Step by Step
Given $$
\int\left[2.4 e^{x}-7\left(3^{x}\right)\right] d x
$$
Thus:
\begin{align*}
\int\left[2.4 e^{x}-7\left(3^{x}\right)\right] d x&= 2.4 e^{x}-\frac{7}{\ln 3}\left(3^{x}\right) +c
\end{align*}