harga 2 meter kain wol dan 3 meter kain kartun Rp.135.000,00.sedangkan harga 3 meter kain wol dan 1 meter kain kartun Rp.115.000,00.Harga 2 meter kain kartun ad

Kelas 8 Matematika
Bab SPLDV

Kain wol = x
Kain katun = y

3x + y = 115.000
y = -3x + 115.000

2x + 3y = 135.000
2x + 3 (-3x + 115.000) = 135.000
2x - 9x + 345.000 = 135.000
-7x = 135.000 - 345.000
x = -210.000 / -7
x = 30.000

y = -3x + 115.000
y = -3 . 30.000 + 115.000
y = -90.000 + 115.000
y = 25.000

Harga 2 meter kain katun
= 2 . y
= 2 . 25.000
= Rp 50.000,00

Jawabannya:

Mapel. : Matematika
Bab. : SPLDV

Pembahasan:

Mis :

x → Kain Wol
y → Kain Katun

Jadi :

* 2x + 3y = 135000 |×1|
3x + y = 115000 |×3|

2x + 3y = 135000
9x + 3y = 345000
--------------------------- -
-7x = -210000
x. = -210000/-7
x = 30000

* 2x + 3y = 135000. |×3|
3x + y = 115000. |×2|

6x + 9y = 405000
6x + 2y = 230000
-------------------------- -
7y = 175000
y = 175000/7
y = 25000

Maka :

Harga 2 meter kain katun
2 × y
= 2 × 25000
= Rp. 50.000 → Jwbnya

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