$\lim_{x\to1}\left(\frac{\left(10^x-9^x-1\right)}{x^2-1}\right)$

$\left(-5\right)+\left(-9\right)-\left(-5\right)+2$

$\frac{\cos\left(x\right)}{\cot\left(x\right)}+\tan\left(x\right)\:\left(\cos\:\left(x\right)\right)\:$

$900x^2-9$

$6a^2+24xy+24y^2$

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

$\int\frac{1}{\left(4x^{2}-1\right)\left(x+7\right)}dx$