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Afla numerele rationale x y z stiind ca x/2=y/5=z/7 si 2x-y-z=4

Răspuns :

x/2=y/5=>x=2y/5
y/5=z/7=>z=7y/5
2x-y-z=2(2y/5)-y-7y/5=4y/5-y-7y/5=-3y/5-y=-8y/5=4=>-8y=20=>y=-5/2
z=7y/5=>z=-7/2
x=2y/5=>x=-1