1) Set up the matrix equation for the least-squares problem. I am getting and m by 1 matrix but I think I should be getting a 2 by 2 matrix.
2) Convert this matrix equation into the normal equation. In particular, use norm notation and dot product notation to write $A^TA$ and $A^Tb$ compactly.
3) Solve this system by inverting the 2x2 matrix and applying it to the right-hand side vector and identify the assumption needed for this solution to exist.