Add 2nd and 3rd
7x + 9z = 11
Multiply 1st by 2 and add to 2nd
10x +5z=0 mutiply red by -10/7 and add to green
-10/7 (9z)+5z = -10/7 (11) solve for z
z = 2
Plug z value into 2nd equation and 3rd equation
2x - 2y = 4 5x -2y = -11 add these two equations
7x = - 7
x = - 1
Now sub in the values of z and x into any of the equations to compute z
2(- 1) + 2y +3(2) = 10
y = 3