Question

9 9/28 - (4 5/21 - x) = 6 2/7

Answer 1

261/28-(89/21-x)=12/7
261/28-(89/21-x)=12/7
261/28-89/21+x=12/7
61/12+x=12/7
x=12/7-61/12
x=-283/84 или - 3,36905

Answer 2

9 9/28-(4 5/21-x)=6 2/79

9 9/28-4 5/21+x=6 2/7

5 1/12+x=6 2/7

x=6 2/7-5 1/12

x=6 24/84-5 7/84=1 17/84

Дополнение к вычислениям:

9/28-4 5/21=9 27/84-20/84=5 7/84=5 1/12