Question

Tentukanlah selesaian dari :
1. x+y=3 dan x+2y=4
2. 2x+y=1 dan 2x-y=1
3. 4x+6y=12 dan 2x+y=13
4. x+y=5 dan x-y=4
5. y=x+2 dan y=4-x

Answer 1

1. x+y = 3 3. 4x+6y =12 | x1 | 4x +6y=12
x+2y =4 2x+ y = 13 | x2 | 4x+2y =26
--------------- - ---------------- -
-y = -1 4y = 14
y = 1 y= 14/4
x+y= 3 2x+y = 13
x+1=3 2x+ 3.5= 13
×= 3-1= 2 2x = 13-3.5
(×,y) = (2,1) 2x = 10.5
x= 5.25 jd (x,y) = (3.5, 5.25)
2. 2x+y = 1
2x-y = 1
---------------- +
4x = 2
x = 1/2
2x+y=1
2(1/2)+y =1
1+y=1
y=1-1=0
(×-y) = (1/2,0)

4. x+y = 5
x-y = 4
--------------- +
2x= 9
x= 9/2
x= 4.5
x+y = 5
4.5+y = 5

y = 0.5
(x,y) = (4.5, 0.5)

5. y= x+2
y= 4-x
maka
y= x+2
y=-x+4
----------- -
y = 6

y=x+2
6= x+2
6-2 =x
4 = x
(x,y) = (4,6)