Solve linear system (Matrices)

[Gina]

Hi, I've got problems in solving the following problem:
Actually, I want to determine the values of a (4x1 matrix) by solving a linear system of equations, whereby the first value of the (4x1 matrix) equals 1. So, there are 3 unknown values. The values of the (3x4 matrix) are known.

(3x4 matrix) * (4x1 matrix) = 0

I attached a word file, where you can see the data.
I tried the following to solve the linear system:

matrix matrix_x = @convert(group_x)
vector(3) vector_nil
vector vector_beta = @solvesystem(matrix_x, vector_nil)

I tried to solve this problem by using the command @solvesystem, but the following error message appears:
Attept to invert or decompose non square matrix in vector vector_beta = @solvesystem(matrix_x, vector_nil)

Is there an alternative? If yes, could you please show me?
Additionally, I have no idea how to insert the value 1 to the (4x1 matrix).
Thanks a lot in advance!!

P.S.: I am using EViews 8!

[trubador]

You can use that command if you arrange your matrices in the following way: