$\sec\left(x\right)^2+\csc\left(x\right)^2=\cos^2\left(x\right).\csc^2\left(x\right)$

$4x^2\left(3x+8\right)$

$\left(1.5-x\right)^2$

$\lim_{x\to\infty}\:\left(7^x+9^x\right)$

$-2x+\frac{8}{4}x+\frac{1}{4}x+x-\frac{5}{6}x$

$\frac{d^2}{dy^2}\left(y^5-3xy\right)$

$\frac{x^2-74}{x-8}$