$\left(3x^4-8y^3\right)\left(3x^4+8y^3\right)$

$-1-3^2-2^2$

$\int\frac{9e^x+3e^{3x}-5}{e^x}dx$

$\left(-416\right)+\left(-235\right)+\left(-315\right)$

$\int\left(\frac{\left(2x^2+1\right)}{\left(x\right)\sqrt{x^2+1}}\right)dx$

$x^2-3x-7$

$\:\int\frac{x^2\sqrt{2+x}}{x}dx$