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Calculați :
[tex] \frac{2}{3 \times 5} + \frac{2}{5 \times 7} + \frac{3}{7 \times 10} + \frac{2}{10 \times 12} [/tex]
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VA ROG AJUTATI-MĂ.
VREAU REZOLVAREA COMPLETĂ SI CORECTA!!!


Răspuns :

Imnultim nr de la numitor, dupa care aducem fractiile la numitorul comun 420.
(2/15)+(2/35)+(3/70)+(1/60)=
(56+24+18+7)/420=
105/420=1/4


[tex] \frac{2}{3 \times 5} + \frac{2}{5 \times 7} + \frac{3}{7 \times 10} + \frac{2}{10 \times 12} \\ \\ \frac{2}{15} + \frac{2}{35} + \frac{3}{70} + \frac{2}{120} \\ \\ \frac{2}{15} + \frac{2}{35} + \frac{3}{70} + \frac{1}{60} = \frac{105}{420} = \frac{1}{4} [/tex]