$3^2+20\left(3\cdot4\right)-6+15$

$\sqrt[3]{x^2}+\sqrt[3]{y^2}=\sqrt[3]{a^2}$

$\left(-0.8x+1\right)^2$

$25ax2-9a$

$ln\left(x\right)=\frac{3}{4}ln\left(81\right)+ln\left(5\right)-3ln\left(8\right)$

$\left(2+x\right)\frac{dy}{dx}=7y$

$\left(\frac{7-3}{4-3}\right)\left(\frac{3+5}{5-3}\right)$