Question

17. Diketahui 1/4x + 2/3y = 2 1/2 dan 3/4x + 1/2y = 3. Nilai 3x + 2y =..

Answer 1

1/4.x + 1/6.y = 4
[x/4 + y/6 = 4]×24
6x + 4y = 96
3x + 2y = 48 ...(1)

1/2.x - 2/3.y = -2
[x/2 - 2y/3 = -2]×6
3x - 4y = -12 ...(2)

3x+2y=48
3x-4y=-12
___________—
6y = 6
y = 10 ...(3)

3x-4y = -12
3x-40 = -12
3x = 28
x = 28/3 ...(4)

maka, 
3x - 2y - 5 
= 3(28/3) - 2(10) - 5 
= 28-20-5
= 3