X + y =9 2y + 3z =7 X - 2z =4 Maka nilai dari (x-y+z) adalah....

(1)-(3),,,,,y+2z = 5......(4)
(4) x 2 ,,,,2y + 4z = 10
2y +3z = 7.....(3)
(4)-(3) -z = 3
z =-3
x - 2(-3) = 4
x +6=4
x=-2
-2 + y = 9
y = 11