$[\sen\left(\alpha\right)-\cos\left(\alpha][\frac{1}{\sen\left(\alpha\right)}+\frac{1}{\cos\thetac\left(\alpha\right)}]$

$-x^2-x+5$

$\int\frac{7}{x^2-5x+6}dx$

$3+2x^2-2x^2-2$

$\left(-7\right).\left(-2\right).2\left(-3\right).\left(5\right).2$

$\left(x+8\right)^2+\left(x-9\right)\left(x-4\right)$

$3x^2y\:-8xy^2$