Question

Aduceti la cel mai mic numitor comun fractiile: a) $\frac{8}{9}$; $\frac{9}{7}$. 
b)$\frac{3}{4}$; $\frac{5}{7}$; $\frac{8}{3}$
c)$\frac{3}{11}$; $\frac{9}{4}$.
d)$\frac{4}{5}$; $\frac{6}{7}$; $\frac{5}{6}$
e)$\frac{5}{12}$; $[tex] \frac{11}{8}$; $\frac{17}{48}$
f)$\frac{2}{35}$; $\frac{1}{70}$; $\frac{3}{140}$

Answer 1

a) 9 = 3²                          8/9 si 9/7, amplifici 8·7/63 si 9·9 /63
    7 = 7                            56/63 si 81/63
   ==========
  c.m.m.m.c = 3²·7  = 9·7 = 63

b) 4 = 2²
    7 = 7
    3 = 3
=============
c.m.m.m.c. = 2²·3·7 = 4·21 = 84
c) 11 = 11
     4 = 2²
==============
c.m.m.m.c. = 2²·11 = 4·11 = 44
d) 5 = 5
    7 = 7
    6 = 2·3
==============
c.m.m.m.c. = 2·3·5·7 = 6·35 =210
e) 12 =2²·3
     8 = 2³
   48 = 2²·2²·3 = 2⁴·3
============
c.m.m.m.c. = 2⁴· 3 = 16·3 = 48
f) 35 = 5·7
   70 = 2·5·7
  140 = 2²·5·7
============
c.m.m.m.c. = 2²·5·7 = 140
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