Maple Matrix for LinearSolve [closed]

Question

With the following matrix,

I'm suppose to use Maple to create the vector b that is column 3 from A and the matrix C that is made from columns 1 to 2 and 4 to 11 of A (in the same order as the columns of A).

And solve the matrix equation [C*x = b] and enter the 9th component of the unique vector solution for x.

I'm able to get the matrix C*x=b, but unable to get the right solution.

Answer 1

Does this give you the same b and C? Do you get the zero-Vector if you try to test your solution x by issuing the command C.x-b? Are you supposed to give the exact rational result or a floating-point approximation?

b:=A[1..-1,3]:     
C:=A[1..-1,[1,2,seq(i,i=4..11)]]:
x:=LinearAlgebra:-LinearSolve(C,b):   
x[9];