Verified answer

Ответ:

[tex]\displaystyle \frac{1}{7} +\frac{1}{9} =\frac{9}{63} +\frac{7}{63} =\frac{9+7}{63} =\frac{16}{63}[/tex]

[tex]\displaystyle\frac{1}{19} +\frac{1}{7} +\frac{1}{13} =\frac{91}{1729} +\frac{147}{1729} +\frac{133}{1729} =\frac{91+147+133}{1729} =\frac{471}{1729}[/tex]

[tex]\displaystyle\frac{1}{4} +\frac{1}{12} +\frac{1}{6} =\frac{3}{12} +\frac{1}{12} +\frac{2}{12} =\frac{3+1+2}{12} =\frac{6}{12}=\frac{1}{2} =0.5[/tex]

Відповідь:

Покрокове пояснення:

   1/7+1/9 = 9/63 + 7/63 = 16/63 ;

   1/19+1/7+1/13 = 91/1729 + 247/1729 + 133/1729 = 471/1729 ;

   1/4+1/12+1/6 = 3/12 + 1/12 + 2/12 = 6/12 = 1/2 .