Question

Diketahui sistem persamaan 3x-5y=-27 dan 4x+2y=-10,maka nilai dari 5x+2y adalah

Answer 1

3x - 5y = -27  |×2| 6x - 10y = -54
4x + 2y = -10 |×5| 20x + 10y = -50
-------------------------------------------------- +
26x = -104
x = -104/26 = -4

subtitusi nilai x :
3x - 5y = -27
3(-4) - 5y = -27
-12 - 5y = -27
-5y = -15
y = -15/-5 = 3

maka,
5x + 2y = 5(-4) + 2(3) = -20 + 6 = -14

maka, nilainya adalah -14

Answer 2

3x - 5y =-27 | x2 |
4x + 2y = -10 | x5 |
———————— -
-14x = 4
x = 3,5

4x + 2y = -10
4(3,5) + 2y = -10
14 + 2y = -10
2y = -10 + 14
2y = 4
y = 2

5x + 2y = ?
5(3,5) + 2(2) = 21,5