4(x-y)-3xy=-14
7(x-y)+4xy=31
x-y=t
xy=s
4t-3s=-14 х4 16t-12s=-56
7t+4s=31 х3 21t+12s=93
37t=37
7+4s=31 4s=24 s=6
x-y=1
xy=6
x=2 y=3
x=-2 y=-3
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4(x-y)-3xy=-14
7(x-y)+4xy=31
x-y=t
xy=s
4t-3s=-14 х4 16t-12s=-56
7t+4s=31 х3 21t+12s=93
37t=37
7+4s=31 4s=24 s=6
x-y=1
xy=6
x=2 y=3
x=-2 y=-3
/////////////////////////////////