Question

Answer 1

`[1/3-1/7-1/13]/[2/3-2/7-2/13].[1/3-0,25+0,2]/[1 1/6-0,875+0,7]+6/7`

`=[1/3-1/7-1/13]/[2(1/3-1/7-1/13)].[1/3-1/4+1/5]/[7/6-7/8+7/10]+6/7`

`=1/2 .[1/3-1/4+1/5]/[7/2(1/3-1/4+1/5)]+6/7`

`=1/2 . 1/[7/2]+6/7`

`=1/2 . 2/7+6/7`

`=1/7+6/7=7/7=1`

Answer 2

\(\dfrac{\dfrac{1}{3}-\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}-\dfrac{2}{7}-\dfrac{2}{13}}.\dfrac{\dfrac{1}{3}-0,25+0,2}{1\dfrac{1}{6}-0,875+0,7}+\dfrac{6}{7}\)

\(=\dfrac{\dfrac{4}{21}-\dfrac{1}{13}}{\dfrac{8}{21}-\dfrac{2}{13}}.\dfrac{\dfrac{1}{3}-\dfrac{1}{4}+\dfrac{1}{5}}{\dfrac{7}{6}-\dfrac{7}{8}+\dfrac{7}{10}}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}.\dfrac{\dfrac{1}{12}+\dfrac{1}{5}}{\dfrac{7}{24}+\dfrac{7}{10}}+\dfrac{6}{7}\)

\(=\dfrac{1}{2}.\dfrac{2}{7}+\dfrac{6}{7}=\dfrac{2}{14}+\dfrac{6}{7}=\dfrac{2}{14}+\dfrac{12}{14}=\dfrac{14}{14}=1\)