Tentukan nilai 2x+y+4z dari persamaan linear tiga variabel berikut! x +z=3 y+z=2 4x+2y+z=8

x+z=3
x=3-z
.
y+z=2
y=2-z
.
4x+2y+z=8 (dgn x=3-z dan y=2-z)
4(3-z)+2(2-z)+z=8
12-4z+4-2z+z=8
-4z-2z+z=8-12-4
-5z=-8
z=-8/-5
z=1.6
.
x=3-z
x=3-1.6
x=1.4
.
y=2-z
y=2-1.6
y=0.4
.
2x+y+4z
=2(1.4)+0.4+4(1.6)
=2.8+0.4+6.4
=9.6