Study guide and 4 practice problems on:

## Lines in 2d can be specified by a point and a normal vector

We can specify a line in 2d by a point $\mathbf{x_0}$ and a normal vector $\mathbf{n}$.
A 2d line with normal vector $\bfn$ is given by $$\bfn\cdot \bfx = b$$ for some $b$.
The 2d line going through $\bfx_0$ with normal vector $\bfn$ is given by $$\bfn \cdot \bfx = \bfn \cdot \bfx_0$$