$\sec\left(x\right)^22=\frac{1}{\sin\left(x\right)^2\cdot\cos\left(x\right)^2}$

$-\left(\sqrt{2}\cdot\:\sin\:\left(2x\right)\cdot\:\cos\:\left(x\right)\right)+\cos\left(x\right)=0$

$100x^2-49y^4$

$3^3\cdot3^1$

$-8a^x+1+8a^x+1$

$3x-2>13$

$\left(3\sqrt{7}+10\sqrt{5}\right)\left(3\sqrt{7}-10\sqrt{5}\right)$