$\left(5a-2b\right)\left(3a-7b\right)$

$\int\frac{2x^3-4x^2-15x+5}{\left(x-4\right)\left(x+2\right)}dx$

$t^2\frac{dx}{dt}=\frac{1}{x}$

$12x^2-\:x+3\:;\:x=-2$

$10n+4+\left(-3n\right)+2$

$\lim_{x\to-\infty}\frac{3x-1}{\sqrt{x^2}-6}$

$f\left(x\right)=\frac{3}{x^2+2x-3}$