$\frac{13}{12}+\left(-\frac{1}{12}\right)$

$\left(\frac{16}{11}z^9r-\frac{1}{3}r^{12}\right)^2$

$\int_1^{\infty}\left(\frac{1}{x\left(6x+7\right)}\right)dx$

$-12-\left(-20\right)$

$2\left(1+2x\right)=10$

$\left(8x^2+9\right)\left(8x^2+y\right)$

$\frac{3yx^2}{x^3y^3}$