$7+x-5x^2-4x+9x^2-8x\:\:\:-\:\:x+3xy+2y-11x-xy+9$

$dy=3xydx$

$5xy-7xy+12xy-14xy-5xy$

$\lim_{x\to\infty}\left(x^{-2}e^{2x}\right)$

$\frac{\left(1-sen\left(x\right)\right)^2+\left(1+sen\left(x\right)\right)^2}{\left(1+sen\left(x\right)\right)\left(1-sen\left(x\right)\right)}$

$\left(\frac{a^{-3}}{b^{-5}}\right)\cdot\left(\frac{a}{b}\right)^4$

$\left(2x^2-5x+4\right).\left(x+2\right)$