Solve a 3x3 Linear System for z

Add the first and third equations to eliminate z: 2x + 3y = 8. Add the second and third: 3x + y = 5, so y = 5 − 3x. Substitute: 2x + 3(5 − 3x) = 8 → −7x = −7 → x = 1, y = 2. Then z = 6 − 1 − 2 = 3. Check the second equation: 2 − 2 + 3 = 3. TI-36X Pro tip: press 2nd, sys-solv, choose 3x3 LIN SYSTEM, enter each row (1, 1, 1, 6), (2, −1, 1, 3), (1, 2, −1, 2), then SOLVE and scroll down to read z = 3.