$\left(-5z^2+z^2-2z+1.7\right)-\left(-z^3-7z^2+z+4.6\right)$

$\int\frac{5x^2-x-6}{x^3+2x-3}dx$

$7ab+5ab-ab+6ab-2ab$

$\lim_{x\to-2.001}\left(\frac{x^2-4}{x+2}\right)$

$-23-5+19-1+4-23-5+19-1+4$

$\lim_{x\to\infty}\left(\frac{x\sqrt{x^2-1}-x-1}{x+1}\right)$

$8a+5a^2-2a+7a^4$