Question

Sistem persamaan linier dua variabel dari 2x+3y=8 dengan 3x+5y=14. jika penyelesaian dari sistem tersebut adalah x=a dan y=b, nilai 4a-3b adalah...

plis jawab

Answer 1

Verified answer

2x + 3y = 8 |x3| 6x + 9y = 24
3x + 5y = 14 |x2| 6x + 10y = 28
dieliminasi -y =-4
y = b = 4

2x + 3y = 8
2x + 3(4) = 8
2x + 12 = 8
2x = 8 - 12
2x = -4
x = a = -2

4a - 3b = 4(-2) - 3(4) = -8 - 12 = -20

Answer 2

Jawab :

6x + 9y = 24
6x + 10y = 28
___________ - 
        -1y = -4
           y = -4/-1
           y = 4

Substitusi ke 1

2x + 3y = 8
2x + 3(4) = 8
2x + 12 = 8
2x = 8 - 12
2x = -4
  x = -4/2
  x = -2

Nilai 4a - 3b = 4(-2) - 3(4)
                    = -8 - 12
                    = -20