$-81-\left(-53\right)$

$9x^2+12x+4=0$

$1-2sin^2x=2sinxcosx$

$\lim_{x\to0}\left(\frac{\tan\left(4x\right)}{\tan\left(7x\right)}\right)$

$\frac{d}{dx}\left(\sqrt{x^3+y^2}=\frac{1}{x}+y\right)$

$\frac{y'}{y}=e^{3+2x}\left(lny\right)$

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