X+2y=-1 dan 2x+5y=-1 tentukan x+y?

Question

Matematika Diposting : 2017-11-18 Diupdate : 2021-11-30 Achilesan

Pertanyaan

Answer 1

ubah x+2y=-1 menjadi x=-1-2y

substitusikan ke

2x+5y=-1

2.(-1-2y) + 5y=-1

-2 -4y +5y=-1

-4y +5y =-1+2

y = 1

substitusi ke

x=-1-2y

x= -1 -2.1

x=-1-2 = -3

jadi nilai

=x+y

=-3 +1

=-2

Answer 2

X+2Y = -1 |x2
2X+5Y = -1 |x1

2X+4Y = -2 | 9Y = -3
2X+5Y = -1 | Y = -3

X+2Y = -1
X+2(-3) = -1
X-6 = -1
X= 6

X+Y = 6+(-3)
= 6-3 = 3