Question

X + Y = 1 , Y+Z=6, X+Y+Z= 4, mka X + Y +Z= ....???

Answer 1

X + Y = 1
y = 1 - X

Y+Z=6
1-X+Z=6
Z= 6-1+X

X+Y+Z = 4
X+1-X+6-1+X = 4
6+X=4
X= -2

jadi
X=-2
Y=1-X=1-(-2)=3
Z= 6-1+X=5+-2=3

jadi X+Y+Z = 4