$$\frac{6x^2+23x^2+4x+15}{x^2+3}$$

$$\left(x+6\right)^2+\left(4x-2\right)^2=\left(5x\right)^2$$

$$5m^2+2v-3mv+2v$$

$$\int\arctan\left(x^4\right)dx$$

$$\frac{1}{2\sqrt{x+1}}$$

$$2y^3-6ay^2-y+3a$$

$$\left(8x^3y^2z^5\right).\left(6x^3yz^2\right)$$