$-4x+6y-6y+3x$

$\lim_{x\to4}\left(\frac{5x^2+7x+2}{x+1}\right)$

$\frac{1+x^{2}}{1-x+x}=\frac{1+x}{1}+\frac{x^{2}}{1-x^{2}}$

$\left(+9\right)x\left(-2\right)$

$49x^6-36y^2$

$\int\frac{3}{2\left(\frac{23}{16}+\left(z+\frac{1}{4}\right)^2\right)}dz$

$\frac{d}{dx}\left(x^2+y^2-5=0\right)$