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

$\left(x+6\right)^2-\left(x+2\right)^2+\left(x-1\right)^2$

$\lim_{x\to0}\frac{\ln\left(1\:+\:sin^2\left(2x\right)\right)}{1\:-\:cos^2\:x}$

$\left(\frac{a}{b}+\frac{2x^2}{3y^4}\right)^2$

$\int_0^{1.4}\left(8te^{-t}\right)dt$

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

$44k^5-66k^4+77k^3$