2x+y=11 3y-z=5 x+2z=1 Maka nilai dari x+y-z=

X + 2Z = 1 , 2Z = 1 – X , Z = (1 – X) / 2

3Y – [ (1 – X) / 2] = 5

6Y/2 – [ (1 – X) / 2] = 10/2

(6Y – 1 + X ) /2 = 10 / 2 , 6Y – 1 + X = 10 , 6Y + X = 11 ,X = 11-6Y

2X + Y = 11 , 2(11-6Y) + Y = 11 , Y = 1 , X = 5 , Z = 2