Question

X + 2y - z = -1
3x - y + 3z = 8
2x + y + 3z = 6

Answer 1

Verified answer

Pers. 1 >> x + 2y - z = -1
pers. 2 >> 3x - y + 3z = 8
pers. 3 >> 2x + y + 3z = 6 >> y + 3z = 6 - 2x (ini sebagai kata kunci)

*masukkan kata kunci ke pers.2*
3x - y + 3z = 8
3x - (6 - 2x) = 8
3x - 6 + 2x = 8
5x = 14
x = 14/5 ✓

*eliminasi pers.1 dan 3*
x + 2y - z = -1 (×1) x + 2y - z = -1
( - )
2x + y + 3z = 6 (×2) 4x +2y + 6z = 12
menjadi
-3x - 7z = -13
3x + 7z = 13
3(14/5) + 7z = 13
7z = 13 - 42/5 = 65/5 - 42/5
7z = 23/5
z = 23/5 ÷ 7
z = 23/5 × 1/7
z = 23/35 ✓

*masukkan ke pers.1*
x + 2y - z = -1
14/5 + 2y - 23/35 = -1 (dikalikan 35)
98 + 70y - 23 = -35
70y + 75 = -35
70y = -110
y = -11/7 ✓