X - 2y =10 3x + 2y =9

Bab Persamaan Linear
Matematika SMP Kelas VIII

x - 2y = 10
3x + 2y = 9
----------------- +
4x = 19
x = 19/4

x - 2y = 10
19/4 - 2y = 10
-2y = 40/4 - 19/4
-2y = 21/4
y = -21/8

(x,y) = (19/4, -21/8)

x-2y=10
3×+2y=9
(ELIMINATION)
x-2y=10×3=3x-6y=30
3×+2y=9×1=3×+2y=9

Maka

,,,8y=21 maka y=21/8=2,625



SUBTITUTION

x-2y=10
x-2(2,625)=10
x-5,25=10
x=10+5,25
×=15,25