$9-3x^2-7x^2$

$2x^2=x+1$

$\frac{\cos\left(y\right)\cdot\tan^2\left(y\right)}{1\cos\left(y\right)}$

$\sqrt[13]{5^{26}}$

$\left(-9x^2-10y\right)^2$

$\frac{cot\left(x\right)}{cos^3\left(x\right)}-\frac{1}{cos^2\left(x\right)}\:=\:\frac{csc\left(x\right)}{1+sen\left(x\right)}$

$y'=10-y$