$\lim_{x\to0}\left(\frac{x\cdot\cos\left(x\right)}{\left(x+1\right)\sin\left(x\right)}\right)$

$\lim_{x\to0}\left(\frac{2b^x-2}{3x}\right)$

$12x^2-15x\ge18$

$\left(3x+1\right)^2=4\left(x+2\right)^2$

$\frac{x^2+18x+32}{x+6}$

$4-u^2z^6$

$\left(\sqrt{b}\cdot\sqrt{5a}\right)^2$