[20]二元一次方程(Help me!~!~!~)

1. X=-3 -2 0 1 4
3X= 9 6 0 3 12

X=-1 0 2 5 6
2X-1= 0 -1 3 9 11

2. X=-3 0 0
Y=0 0 0

3.1A) X=5
2X+Y=8
2*5+Y=8
10+Y=8
10+Y-10=8-10
Y=-2
1B)Y=X
3X-5Y=4
3-5XY=4
-2XY=4
-2XY+2=4+2
XY=6
2A)X+Y=5,X-Y=3,X=3,Y=5
X-2Y=-2 X+2Y=14
3-2*5=-2 3+2*5=14

http://www.photo-host.org/img/89986298339356tz8.png

1)
-9,-6,0,3,12
-3,0,3,9,11

2.1)
-6,-3,-3
題目b睇唔明，好你似少左過X

2.2)
i)Y=X-3
put 1 into X
Y=-2

ii)Y=X-3
put -1 into Y
X=2

iii)Y=X-3
put 2.6 into x
X=-0.4

iv)Y=X-3
put 0 into Y
X=3

v)Y=X-3
put 0 into X
Y=-3

3.1.a)
X=5
2X+Y=8

2(5)+Y=8
Y=3
X=5

3.1.b)
X=Y
3X-5Y=4

3X-5(X)=4
X=Y=-2

3.2.a)
X+Y=5
X-Y=3

2X=8
X=4
put 4 into X
4+Y=5
Y=1

3.2.b)
X-2Y=-2
X+2Y=14

2X=12
X=6
put 6 into X
6-2Y=-2
Y=4

3.3.a)
X+Y=3/4
2X-Y=0

3X=3/4
X=1/4
put 1/4 into X
1/4+Y=3/4
Y=1/2

3.3.b)
(2X+3Y)/3=9
(2X+2Y)/11=3

2X+3Y=27
2X+2Y=33

Y=-6
put -6into Y
2X+3(-6)=27
X=22.5