Can you please help me with this

Let A = 1 -2 and b = ( 3 1 -4 2 )t

-1 2

0 3

2 5

(a) Find a least-squares solution ofAx = b.

(b) Find the orthogonal projection ofbonto the column space ofA.

(c) Compute the least-squares error ( in the solution of part ( a )).

Thank you!