$\int^2-2\left(x^3\cos\left(\frac{x}{2}+\frac{1}{2}\right)\right)\sqrt{4-x^2}dx$

$x^2\left(x^2+3y^2\right)^2-y^2\left(y^2+3x^2\right)^2$

$x\cdot y=x+y-1$

$\left(3x-7\right)\left(x+2\right)_{-2x^2}\le\left(x+2\right)^2$

$\left(x^2-7\right)\cdot\left(3x^3+6x+5\right)$

$-4x+5x+2$

$4x^2+9y^2+8x-36y+39=0$