X1 – x2 + x3 –2×4 = 8 2×1 – x2 + 2×3 – x4 = 5 -x1 + x2 + 2×3 – x4 = 4 x1 + 2×2 + 4×3 + x4 = 5
Jawab:
Penjelasan dengan langkah-langkah:
x1 – x2 + x3 –2×4 = 8
2×1 – x2 + 2×3 – x4 = 5
-x1 + x2 + 2×3 – x4 = 4
x1 + 2×2 + 4×3 + x4 = 5
Misal :
x1 = p, x2 = q, x3 = r, x4 = s
p – q + r –2s = 8
2p – q + 2r – s = 5
-p + q + 2r – s = 4
p + 2q + 4r + s = 5
p = 8 + q – r + 2s
2 (8 + q – r + 2s) – q + 2r – s = 5
16 + 2q – 2r + 4s – q + 2r – s = 5
q + 3s = 5 – 16
q + 3s = -11
q = -11 – 3s
-(8 + q – r + 2s) + (-11 – 3s) + 2r – s = 4
-8 – q + r – 2s – 11 – 3s + 2r – s = 4
-8 – (-11 – 3s) + r – 2s – 11 – 3s + 2r – s = 4
-8 + 11 + 3s + r – 2s – 11 – 3s + 2r – s = 4
-3s + 3r = 4 + 8 – 11 + 11
-3s + 3r = 12
-s + r = 4
r = 4 + s
8 + (-11 – 3s) – (4 + s) + 2s + 2(-11 – 3s) + 4(4 + s) + s = 5
8 – 11 – 3s – 4 – s + 2s – 22 – 6s + 16 + 4s + s = 5
(-3 – 1 + 2 – 6 + 4 + 1)s = 5 – 8 + 11 + 4 + 22 – 16
-3s = 18
s = 18/(-3) = -6
r = 4 + (-6) = -2
q = -11 – 3(-6) = -11 + 18 = 7
p = 8 + 7 – (-2) + 2(-6) = 8 + 7 + 2 – 12 = 5
Jadi, x1 = 5, x2 = 7, x3 = -2 dan x4 = -6