Express the following systems of equations in matrix form as A x
= b. What is the rank of A in each case (hint: You can find the
rank of a matrix A by using rank = qr(A)$rank in R. For each
problem, find the solution set for x using R.
a. X1+5X2+2X3=5
4X1-X2+3X3=-8
6X1-2X2+X3=0
b. 3X1-5X2+6X3+X4=7
4X1+2X3-3X4=5
X2-3X3+7X4=0
X2+3X4=5