I assume you are being asked to solve these equations. Since there wasn't an explanation as to how you are expected to solve them, I chose to demonstrate how to use a calculator matrix function. You can find matrix calculators online. My instructions are for a TI-84
Push the blue 2nd button then push x^-1 button (it says matrix above this button in blue)
Arrow over to edit to change the dimensions of the matrix and to put in your values. You have 3 equations (3 rows) and 4 terms (4 columns) so you put a 3x4 in for the dimension and the coefficients (see images).
You use the rref option in the math column in matrix to calculate the answer.
The numbers at the end are the solutions. x = -4, y = 2, z = -1
Push the blue 2nd button then push x^-1 button (it says matrix above this button in blue)
Arrow over to edit to change the dimensions of the matrix and to put in your values. You have 3 equations (3 rows) and 4 terms (4 columns) so you put a 3x4 in for the dimension and the coefficients (see images).
You use the rref option in the math column in matrix to calculate the answer.
The numbers at the end are the solutions. x = -4, y = 2, z = -1