Least-squares Solution z of the Overdetermined System

ktcyper03

Find the Least-squares Solution z of the Overdetermined System
|-3 1 | | 70 |
| 1 1 | x = | 21 |
|-7 1 | | 110 |
| 5 1 | |-35 |

Excuse my poorly typed notation as that is supposed to be a matrix times x = another matrix.

TKHunny

If your 4x2 matrix is A, have you considered multiplying from the left with $$\displaystyle \left[\left(A^{T}\cdot A\right)^{-1}\cdot A^{T}\right]$$?

CaptainBlack