Diketahui 3x+4y=7 dan -2x+3y=-16 nilai 2x-7y

3x + 4y = 7 ........ Persamaan 1
-2x + 3y = - 16 ........ Persamaan 2

Persamaan 1 :
3x + 4y = 7 (dikali 2)
6x + 8y = 14

Persamaan 2 :
-2x + 3y = - 16 (dikali 3)
-6x + 9y = - 48

Eliminasi :
6x + 8y = 14
- 6x + 9y = - 48
————————— +
17y = - 34
y = - 2

6x + 8y = 14
6x + 8(-2) = 14
6x = 14 + 16
6x = 30
x = 5

Nilai 2x - 7y
= 2(5) - 7(-2)
= 10 - (- 14)
= 24