[tex] \frac{5}{7} -( \frac{8}{3} -x)= \frac{2}{5}
[tex] \frac{25}{35}- \frac{14}{35} = \frac{8x}{3}
\frac{9}{35} = \frac{8x}{3}
35*8x=9*3
280x=27
x=280/27
x=10,(370)[/tex] \frac{5}{7} - \frac{2}{5}= \frac{8x}{3} amplificam prima fractie cu 5 iar a doua cu 7
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