$\lim_{y\to0}\left(\frac{y-3sin\left(y\right)cos\left(y\right)}{tan\left(y\right)-y}\right)$

$x-7=2x+1$

$2cos^23x+6cos3x=3$

$\left(3\left(x+4\right)-5\right)\left(2\left(x+4\right)^2-3\right)$

$\lim_{x\to\infty}\left(\frac{12e^x}{7\sqrt{x}}\right)$

$\frac{\sqrt{168x^4}}{\sqrt{6x}}$

$2xy^2+1-4xy^2+5x+23xy^2-3xy^2$