$-1-9-10$

$\lim_{x\to0}\left(\frac{9^x-1^x}{x}\right)$

$\tan\left(x\right)\tan\left(x-y\right)=1$

$\frac{2}{3}\left(9x-12\right)$

$\int\frac{\left(3x+7\right)}{\left(x-1\right)\left(x+2\right)\left(x-3\right)}dx$

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

$-7y+2y-y-3y+2y$