$-6+\left[15-\left\{\left(1+4\right)-\left(3-2\right)+3\right\}+7\right]$

$1+\frac{\senx\cdot\ctg^{2}x}{1+\senx}=\csc x$

$2\left(5x-3\right)=9x+7$

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

$\sqrt[3]{x^2y^5}\cdot\sqrt[2]{x^3y^5}$

$\left(7^8\cdot3^5\right)^2$

$5y^2-6y$