Question

Jika x=a dan y=b adlh penyelesain dri 2x+3y=2 dan 3x+4y=2
maka nilai 2a-7b adlh

Answer 1

Eliminasi x untuk memperoleh nila y
2x + 3y = 2 ×3 =6x + 9y = 6
3x + 4y = 2 ×2 = 6x + 8y= 4 -
y = 2

subtitusi y =2 ke salah satu pers. untuk mendapatkan nilai x
2x + 3y = 2
2x + 3(2) = 2
2x + 6 = 2
2x = 2 - 6
x = -4/2
x = -2

nilai 2a - 7b
= 2( -2) - 7(2)
= -4 - 14
= - 18

Answer 2

2x + 3y = 2 | kali 3
3x + 4y = 2 | kali 2
__________________
6x + 9y = 6
6x + 8y = 4
___________ { - }
y = 2

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

A = x = -2
B = y = 2

2a - 7b =
2(-2) - 7(2) =
-4 - 14 =
-18

#semoga membantu..