$\left(0.3x^2+0.2x^4\right)\cdot\left(0.3x^2-0.2x^4\right)$

$5x+y=3$

$\frac{3}{4}^5\cdot1.3^5\cdot\frac{3}{7}^2$

$\ln\left(x^8\right)-\ln\left(x^5\right)=3$

$\int_1^{\infty}\frac{\frac{1}{2}\left(x^2\right)}{x^3+1}-\frac{1}{3x+1}dx$

$9x^2-42xy+49y^2$

$\frac{dx}{dy}4\left(x^2+1\right)x\left(\frac{\pi}{4}\right)=1$