Projection of a convex set in $\mathbb R^n$ onto $\mathbb R^2$

Question

Suppose $A$ is an $n\times n$ matrix and $b$ is an $n\times 1$ column vector.

$$X=\{ x\in \mathbb R^n: A x\leq b\}$$

Is it possible to compute the projection of $X$ on $(x_1,x_2) $ manually and analytically? That is,

$$X_{1,2}=\{ (x_1,x_2)\in \mathbb R^2: x\in X\}$$

Thanks.