Question

Tentukan penyelesaian sistem persamaan berikut dengan metode subtitusi, untuk x, y ∈ R !
1. x = y dan x + y = 6
2. 2x = y - 10 dan x = 2y + 8
3. x = y - 10 dan x = 2y + 8
4. x - 2y = 2 dan 3y - 5x = -24
Tolong dijawab yaa.....

Answer 1

X = y
x + y = 6
y + y = 6
2y     = 6
y        = 6
x = y = 6

x = 2y + 8
2x = y - 10
2(2y + 8) = y - 10
4y + 16 = y - 10
3y = -26
y = -8 2/3
x = 2y + 8 = 2(-26/3) + 8 = -52/3 + 8 = -28/3 = - 9 1/3

x = y - 10
x = 2y + 8
y - 10 = 2y + 8
-18 = y
x = y - 10 = -18 - 10 = -28

x - 2y = 2 => x = 2y + 2
3y - 5x = -24
3y - 5(2y +2) = - 24
3y - 10y - 10 = -24
14 = 7y
2 = y
x = 2y + 2 = 2(2) + 2 = 4 + 2 = 6