Question

Tolong kerjakan cepatnya soalnya besok di kumpul ! tolong
yang dikerjain yang nomornya di bulatin

Answer 1

X + 3y = -28
x + 3(2x) = -28
x + 6x = -28
7x = - 28
x = -28 : 7
x = -4

Answer 2

2)  y = 2x 

substitusi

x + 3y = -28
x + 3(2x) = -28
x + 6x = -28
7x = -28
x = -4

x + 3y = -28
-4 + 3y = -28
3y = -28+4
3y = -24
y = -8

8)  x + 2y = 5
    2y = 5 - x
      y = 5 - x
            -------
                 2

substitusi :

4y - 3x = 0
4(5-x/2) - 3x = 0
20-4x/2 - 3x = 0
10 - 2x - 3x = 0
-5x + 10 = 0
-5x = -10
x = 2

substitusi x = 2

4y - 3x = 0
4y - 3(2) = 0
4y - 6 = 0
4y = 6
  y  =  6/4
  y = 3/2