Frazione

6/5 -  (7/11 - 1/5 ) x (5/7 + 1/14) =

mcm (11; 5) = 55;  mcm (7;14) = 14;

= 6/5 -  (35/55 - 11/55) x (10/14 + 1/14) =

= 6/5 - 24/55 x 11/14 =

= 6/5 - (24 x 11) /(55 x 14) ;     (11 si semplifica con 55, resta 1/5;  24 si semplifica con 14 , si semplifica per 2;  resta 12/7);

= 6/5 - (12 x 1) /(5 x 7) =

= 6/5 - 12/35=

mcm(5; 35) = 35;

= 42/35 - 12/35 =

= 30/35 = (semplificando per 5):

= 6/7.

Ciao  @gianvi

6/5-(7/11-1/5)x(5/7+1/14)

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$\small \dfrac{6}{5}-\left(\dfrac{7}{11}-\dfrac{1}{5}\right)·\left(\dfrac{5}{7}+\dfrac{1}{14}\right)=$

$\small =\dfrac{6}{5}-\left(\dfrac{35-11}{55}\right)·\left(\dfrac{10+1}{14}\right)=$

$\small =\dfrac{6}{5}-\dfrac{\cancel{24}^{12}}{\cancel{55}_5}·\dfrac{\cancel{11}^1}{\cancel {14}_7}=$

$\small =\dfrac{6}{5}-\dfrac{12}{5}·\dfrac{1}{7}=$

$\small =\dfrac{6}{5}-\dfrac{12}{35}=$

$\small =\dfrac{42-12}{35}=$

$\small =\dfrac{\cancel{30}^6}{\cancel{35}_7}=$

$\small =\dfrac{6}{7}$