8x-4y=4 2x+3y-21=0 Cari dengan cara subtitusi dan eliminasi

◆ Eleminasi
8x - 4y = 4 | x1
2x + 3y = 21 | x4

8x - 4y = 4
8x + 12 y = 84
-----------------------( - )
- 16y = - 80

y = [tex] \frac{80}{16} [/tex]

y = 5

◆ Substitusi
8x - 4y = 4

8x - (4 x 5) = 4

8x - 20 = 4

8x = 4 - 20

8x = - 16

x = [tex] \frac{-16}{8} [/tex]

x = - 2

substitusi

8x-4y =4 ---> 2x-y = 1 ---> 2x = y+1

2x + 3y =21
(y+1) + 3y = 21
4y =20
y = 5

2x = y + 1
2x = 5 + 1
2x = 6
x = 3

eliminasi

2x-y = 1
2x+3y = 21
---------------- -
-4y = -20
y = 5

2x - 5 = 1
2x = 6
x = 3