$\frac{\left(x+h-x\right)}{h\left(\sqrt{x}\:+h+\sqrt{x}\right)}$

$\frac{dy}{dx}=\ln\left(x+9x^2\right)$

$6\cdot\:\left(3\right)^2-\left(7\right)\left(3\right)+2$

$f\left(x\right)=\frac{3x-1}{x}-\left(5x-x^2\right)^2$

$4\cos\left(30\right)^2+2\sin\left(30\right)$

$12x+11y=31$

$\int\frac{x+2}{\left(x+3\right)\left(x+4\right)\left(x+1\right)}dx$