Question

Himpunan penyelesaian dari sistem persamaan : x - 2y = 10 dan 3x + 2y = 12 adalah...
A. {( -2, -4 )}
B. {( -2, 4 )}
C. {( 2, -4 )}
D. {( 2, 4 )}
Pake caranya ya

Answer 1

X -2y = 10 -----> x = 10 +2y
3x +2y = 12

3x +2y = 12
3(10 +2y) +2y = 12
30 +6y +2y = 12
8y = 12 -30
8y = -18
y = -18/8
y = -2 1/4

x = 10 +2y
   = 10 +2(-2 1/4)
  = 10 -36/8
  = 44/8
  = 5 1/2

Jadi, HP = {5 1/2, -2 1/4}.
Tidak ada jawabannya.

Answer 2

X - 2y = 10
3x + 2y = -2
-----------------------------------  +
4x = 8
x = 8/4
x = 2

x-2y = 10
2-2y = 10
-2y = 10-2
-2y = 8
y = 8/-2
y = -4

HP = {2, -4}

Jawabannya c.
Maaf, kalau salah.