Question

Diketahui sistem persamaan: 3x + 2y = -2 dan 5x - y = 14 nilai dari 2x + 4y =

Answer 1

3x+2y=-2
10x-2y=28
_____________+
13x=26
x=2

3(2)+2y=-2
2y=-8
y=-4

2x+4y = 4-16=-12

Answer 2

3x + 2y = -2 (*1)
5x - y = 14 (*2)

menjadi :
3x + 2y = -2
10x - 2y = 28
-------------- +
13x =26
x =26/13
x =2

3x + 2y = -2
3(2) +2y = -2
6 + 2y = -2
2y = -2 - 6
2y = -8
y = -8/2
y = -4

maka, 2x + 4y = 2 (2) + 4 (-4)
= 4 -16
= -12