教我做幾條聯立二元一次方程 quick quick

3x-2y=2.........(1)
x-y/2=-4........ (2)

(2)*4-(1):

4x-2y - 3x+2y = -16-2

x = -18,代入(1):

3(-18)-2y=2

y=-28

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3x/2+y=15..........(1)
9x-2y=18 .......... (2)

(1)*2 + (2) :

3x+2y + 9x-2y = 15*2 + 18

12x = 48

x=4,代入(1):

3*4/2 + y = 15

6+y=15

y=9

3x-2y=2---------(1)
x-y/2=-4
4x-2y=-16----------(2)
(2)-(1):
4x-2y- x+2y=-16-2
x = -18
x = -18代入(1)
3(-18)-2y=2
y=-28
3x/2+y=15
3x+2y=30..........(1)
9x-2y=18 .......... (2)
(1)+(2):
3x+2y+9x-2y=30+18
12x = 48
x=4
x=4代入(1)
12/2+y= 15
6+y=15
y=9