$\left(1-\sin^2x+\cos^2x\right)^2+4\sin^2x\cos^2x=4\cos^2x$

$\int x\sin\left(\frac{1}{7}x\right)dx$

$\lim_{x\to-\infty}\left(\frac{2x+8}{x^2+2}\right)$

$3y+13=28$

$2x\cdot x+1\cdot x+2$

$10x-4<2x+10$

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