Diketahui sistem persamaan linear 3x+4x=15 dan x+5y=60. Nilai dari (2x-y) =

Kelas 8 Matematika
Bab Persamaan Linear

x + 5y = 60
x = -5y + 60

3x + 4y = 15
3 (-5y + 60) + 4y = 15
-15y + 180 + 4y = 15
-11y = 15 - 180
y = -165/-11
y = 15

x = -5y + 60
x = -5 . 15 + 60
x = -75 + 60
x = -15

2x - y
= 2 . (-15) - 15
= -30 - 15
= -45