X-y=7
x²-y²=(x-y)(x+y)=14 →x+y=14/7=2
2x=2+7=9 x=3.5 y=2-x=2-3.5= -1.5
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2/ аналогично x-y=15/3=5 2x=5+3=8 x=4 y=x-5=4-5= -1
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3. x-y=24/4=6 x+y=4 2x=10 x=5 y=4-x=4-5= -1
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4. x+y=8/2=4
x-y=2→ 2x=4+2=6 x=6/2=3 y=x-2=3-2=1