penyelesaian sistem persamaan 2x - y = 5 dan x +2y = 9 adalah x dan y l. Nilai 4x - 5y adalah

Gunakan Metode Subtitusi

x + 2y = 9
x = 9 - 2y........ (1)

2x - y = 5
2(9 - 2y) - y = 5
18 - 4y - y = 5
-5y = 5 - 18
-5y = -13
y = 13/5
y = 13/5 ✔

x = 9 - 2y
x = 9 - 2(13/5)
x = 9 - 26/5
x = 45/5 - 26/5
x = 19/5

Jadi,
= 4x - 5y
= 4(19/5) - 5(13/5)
= 76/5 - 13
= 76/5 - 65/5 ✔
= 11/5
= 2 ¹/5

2x-y=5. |2| 4x-2y=10. x+2y=9
x+2y=9 |1| x+2y=9+ 19/5+2y=9
5x=19. 2y=9-19/5
x=19/5. y=13/5
4x-5y=4(19/5)-5(13/5)
=76/5-13
=11/5