Question

Himpunan penyelesaian dari sistem persamaan linear x + y = -4 dan 2x - y = 1 adalah...
Tolong dengan caranya...

Answer 1

X + y = - 4
2x - y = 1
_________ +
3x = - 3
  x = - 1
  y = - 3
HP: {(x,y) = (-1,-3)}

Answer 2

X+y = -4
x = -4-y ...............[1]

2x- y = 1 [2]
substitusi [1] ke [2] didapat
2(-4-y) - y =1
-8-2y-y = 1
-8 -3y = 1
-3y = 1+8
-3y = 9
y = 9/-3 = -3

substitusi ke [1] didapat
x = -y-4
x = -(-3)-4
x = 3-4
x = -1

HP = {(-1,-3)}