$x^2y^2z^2+3x^2y^2z^2$

$\lim_{\left\{x\to inf\right\}}\left(1-\frac{7}{x}\right)^x$

$\csc^4x-\csc^2x$

$x^2-7x+12,25$

$\int\left(\sqrt{6+y}\left(y+2\right)^2\right)dy$

$\lim_{x\to3}\left(\frac{ex^2-e^9}{x-3}\right)$

$3x-5y\sqrt{x^2+1}\frac{dy}{dx}=0,\:y\left(0\right)=5$