p + q + r = 12 (1) x2
2p - q + 2r = 12 (2)
3p + 2q - r = 8 (3)
eliminasi (1) dan (2)
p + q + r = 12
2p - q + 2r = 12
________________ +
3p + 3r = 24 (4)
eliminasi (1) (3)
2p + 2q + 2r = 24
3p + 2q - r = 8
__________________ -
-p + 3r = 16 (5)
Eliminasi (4) dan (5)
p + r = 8
-p + 3r = 16
_____________ +
4r = 24
r = 24/4
r = 6
Baca Juga: Bocoran Soal Ujian PTS Ganjil Matematika Kelas 10 SMA Tahun 2021 Bagian 1
kita substitusikan adik-adik :
p + r = 8
p + 6 = 8
p = 8 - 6
p = 2
p + q + r = 12
2 + q + 6 = 12
q = 12 - 6 - 2
q = 12-8
q = 4