Question 381303
x/4-y/12=-1
LCD =12
3x-y /12 =-1multiply by 12
3x-y=-12.........................1

x/3+y/9=-2
lCD=9
(3x+y)/9 = -2
multiply by 9
3x+y=-18.........................2

Add (1)&(2)
6x=-12+-18
6x=-30
/6
x=-5
...
plug value of x in 2 
-15+y=-18
+15   +15
y=-3
...
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