$\left(5-y\right).\left(5+y\right)$

$\lim_{x\to0}\left(\frac{e^x-e^{-x}}{\ln\left(1-x\right)}\right)$

$\lim_{x\to\infty}\left(\frac{x^3+x}{e^x}\right)$

$\frac{2}{7}x+8=\frac{2}{3}x$

$\left(+43\right)\cdot\left(-94\right)$

$\frac{x^2+3x}{\sqrt{x+4}}$

$\int_1^{\infty}\left(\frac{1}{x^4\sqrt{1+x^2}}\right)dx$