$\int^7\left(\frac{3}{x^2}-1\right)dx$

$-\left(-7\right)\cdot\left(-5\right)\cdot\left(-3\right)\cdot\left(-2\right)$

$x^2+x+6x-2$

$\frac{3x^3-2x^2+5}{-3+x^2}$

$4\cos^2x=5+4\sin x$

$\lim_{x\to\infty}\left(\frac{x^3-4}{x^2+1}\right)$

$\left(\frac{x}{3}-4\right)\left(\frac{x^2}{9}+\frac{4x}{3}+16\right)-\frac{3x^2}{5}\left(\frac{5x}{9}+\frac{5}{x^2}\right)$