jika 7p + 4q =2 dan 4p + 2q =2 maka nilai dari 3p +5q adalah?
Matematika
putrypitaloka
Pertanyaan
jika 7p + 4q =2 dan 4p + 2q =2 maka nilai dari 3p +5q adalah?
2 Jawaban
-
1. Jawaban Nooer
Memakai cara eliminasi
7p + 4q = 2 |x4|
4p + 2q = 2 |x7|
____________
28p + 16q = 8
28p + 14q = 14
____________ -
2q = -6
q = -6/2
q = -3
7p + 4q = 2
7p + 4(-3) = 2
7p + (-12) = 2
7p = 2 + 12
7p = 14
p = 14/7
p = 2
3p + 5q = 3(2) + 5(-3)= 6 + (-15) = -9 -
2. Jawaban andhikahanif
persamaan
7p + 4q = 2
4p + 2q = 2 [x2] 8p + 4q = 4
eliminasi
8p + 4q = 4
7p + 4q = 2
-----------------(-)
p = 2
substitusi
4p + 2q = 2
4(2) + 2q = 2
8 + 2q = 2
2q = 2 - 8
2q = -6
q = -6/2
q = -3
maka nilai 3p +5q
= 3(2) +5(-3)
= 6 + (-15)
= 6 - 15
= -9