$2a^2-ab+2ab-b^2$

$sec^4x\cdot tan^2x=tan^2x\cdot sec^2x\cdot sec^2x$

$\lim_{x\to\infty}ln\left(1+\left(\frac{0.1}{x}\right)\right)^x$

$-84+-15+84+88$

$-12sen\left(3x\right)cos\left(x\right)$

$x+8\le4$

$-4x+\left(x+1\right)^2-3\left(\frac{3-2x}{5}+\frac{1}{3}\right)<=-\left(x+1\right)^2$