Question 358650
2x-y=-4 MULTIPLY BY 2 & ADD.
-4x+2y=6
4x-2y=-8
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0x+0x=-2 NO unique solution for x or y.

2t+4v=6 
-t-2v=-3 multiply by 2 & add
-2t-4v=-6
2t+4v=6
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0t+0t=0 NO unique solution for x or y.