$\frac{x^4-2x^3-15x^2+55x-270}{x-5}$

$8cos\:b+\sqrt{52}=0$

$\frac{d^2}{dx^2}\:y\:y\:x\sqrt{x+1}$

$\sec\left(x\right)-\frac{1}{sec\:x}=\sin\left(x\right)\tan\left(x\right)$

$log\left(x+20\right)-log\left(x+2\right)=logx$

$x^4+x^3-19x^2-49x-30$

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