$+7+3+5+1+9+8+2+6$

$\lim_{x\to1}\left(\frac{\sqrt{x+1}}{x+1}\right)$

$f\left(x\right)=\left(x+5\right)\left(x+9\right)$

$\int\frac{x^3+1}{x^4-3x^3+3x^2-x}dx$

$\frac{1-\cos^{2}\left(180^{\circ}-x\right)}{\cos x\cdot\sin\left(90^{\circ}-x\right)}$

$5b+6=21$

$\frac{x^3+y^3}{\left(x+y\right)^2-3xy}-y$