Consider the overdetermined system of equations 2-6-18 0-2 4 -32 Ar= = 8 12 16 22 b. 4 4 2 26 0 0 -30 (a) Using the GivensRollup code, reduce A to a row echelon matrix R using Givens rotations. Apply the same rotations to the right hand side vector b to get a new right hand side vector c. (b) Find the least squares solution 2* to Az = b using the row echelon matrix R and new right hand side e you found in part (a) of this question. Do this bit by hand; the numbers should all be multiples of 10 and the solution a should be integer. (c) Without doing any further calculation, what is the length of the residual vector b - Az* ??