$\lim_{x\to9}\left(\frac{x^2-81}{3x}\right)$

$\int-48xe^{4x^2+3}dx$

$\int sen^2\left(6t\right)dt$

$\lim_{x\to2}\frac{5x^3}{x^2-3x+2}$

$20-\left(30-37\right)+\left(18+25\right)-\left(-7\right)-20$

$f\left(x\right)=5\left(x^2+3x-2\right)-\left(2x+4\right)^2$

$j\int_1^2\:x\sqrt{x-1}dx$