please answer question

Consider the overdetermined system Ax: b E , where | MN | 0005' CilCDCJII Ol' The following is a "thick" QR decomposition of the coefficient matrix which you may used without proof. 21 2 o A: '33'30 3'30 3 3000 33 3 00 01 (a) Write down the normal equations which define the solution st to Ax: b in the least squares sense. No need to solve these equations! (b) Write down a "thin" QR decomposition for A. (c) Using the given QR decomposition (thick or thin), find the solution st to Ax= b in the least squares sense