$\lim_{x\to10}\frac{10x}{2x+5}$

$\left(b^7+12\right)\left(b^7-5\right)$

$\int-2e^x\left(e^x+5\right)^{-4}dx$

$-3x\left(5x-7x^3y-4x^2y\right)$

$\frac{\left(-72\right)}{\left(-3\right)}$

$\lim_{x\to2}\sqrt{\frac{\left(t+4\right)\left(t-2\right)^2}{\left(3t-6\right)^2}}$

$\int\left(5x+2\right)^2dx$