1. x-y=y dan 2(x-y)+y=9 2. 2kg salak dan 5kg cabe 136.200 4kg salak dan 6kg cabe 168.400 berapa 10kg salak dan 10kg cabe? buat besok. yang jwb sekarang poin 25

1. x-y = y dan 2(x-y)+y= 9
= x-y-y = 0 dan 2x-2y + y = 9
= x-2y = 0 dan 2x-y = 9
= x-2y = 0 ... pers 1
2x-y = 9 ... pers 2
#Kalikan pers 1 dengan x2 sehingga akr² bru
2x-4y = 0
2x-y = 9
_________ -
0 -3y = -9
y = -9/-3
y = 3

#Subsitusi y = 3 ke pers 1 sehingga
x-2y = 0
x-2(3) = 0
x-6 = 0
x = 6 sehingga nilai x = 6 dan y = 3



2. misal x = salak dan y = cabe
sehingga soal cerita trsbut dpt di ubah ke dlm bentuk SPLDV sehingga akan =
2x + 5y = 136.200 ... pers 1
4x + 6y = 168.400 ... pers 2

kalikan pers 1 dengan x6 dan pers 2 dengan x5 sehingga persamaan yg bru :
12x + 30y = 816.200
20x + 30y = 840.400
__________________ -
-8x +0 = -24.400
-8x = -24.400
x = -24.400 / -8
x = 3.005

#Subsitusi x = 3.005 ke pers 1
= 2x + 5y = 136.200
2(3.005) + 5y = 136.200
12.002 + 5y = 136.200
5y = 136.200 - 12.002
y = 124.198 / 5
y = 24,33

Didapat nilai 1 salak = 3.005 dan satu cabai = 24.303

1. x-y=y 2(x-y)+y = 9
x-y-y = 0 2x-2y+y = 9
x-2y =0 (pers 1) 2x-y = 9 (pers 2)
Eliminasi pers 1 & 2
x-2y = 0 dikali 1 x-2y = 0
2x-y = 9 dikali 2 4x-2y = 18 (dikurang)
-3x = -18
x = 6
Subtitusi ke pers 2
2x-y = 9
2(6)-y = 9
12-y =9
-y = 12-9
-y = 3
y = 3+1
y = 4

2. Misal : salak = x
cabe = y

Eliminasi
2x +5y= 136200 (x6) 12x +30y= 817200
4x+6y=168400 (x5) 20x+30y= 842000
-8x = -24800
x = 3100
Subtitusi
2x + 5y = 136200
2(3100) + 5y = 136200
6200 + 5y = 136200
5y = 136200 - 6200
5y = 130000
y = 26000

Jadi 10kg salak dan 10 kg cabe
(10x3100) + ( 10x26000 )
= 31000 + 260000
= 291000