$-\:18\:+\left\{-\:2\:-\:\left[9-3\right]\right\}\:$

$\log_b\left(\frac{.39}{.86}\right)$

$\left(x-5\right)^2\le0$

$\left(\sqrt{2}x^2-\sqrt{2}y^2\right)^2$

$\frac{1+\cos\left(x\right)}{2-\cos\left(x\right)}=1$

$\int\frac{sen^3\left(x\right)}{\sqrt{cos\left(x\right)}}dx$

$3\left(2a+b\right)-4a\left(b+c\right)-2c\:\left(a-b\right);\:x=7;\:y=10$