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Daca x²+y²=58 si x-y=4, calculati x+y. Multumesc!

Răspuns :

[tex] x^{2} + y^{2} =58=>-( x^{2} - y^{2})=58=>-(x-y)(x+y)=58=> \\ -4(x+y)=58=>x+y= -14,5[/tex]
proba: -4*(-14,5)=58