Упростите выражение раскрывая скобки Д)4 2/7-(7 1/3- 4 2/7)= E)9 7/9-(2

Упростим наши выражения по деяньям,

Д) 4 2/7 - (7 1/3 - 4 2/7), 

1) (7 1/3 - 4 2/7) = (7 * 3 + 1)/3 - (4 * 7 + 2)/7 = 22/3 - 30/7 = (22 * 7)/21 - (30 * 3)/21 =

154/21 - 90/21 = (154 - 90)/21 = 64/21,

2) 4 2/7 - 64/21 = (4 * 7 + 2)/7 - 64/21 = 30/7 - 64/21 = (30 * 3)/21 - 64/21 = 90/21 - 64/21 = (90 - 64)/21 = 26/21 = 1 5/21,

E) 9 7/9 - (2 1/2 - 2/9),

1) (2 1/2 - 2/9) = (2 * 2 + 1)/2 - 2/9 = 5/2 - 2/9 = (5 * 9)/18 - (2 * 2)/18 = 45/18 - 4/18 =

(45 - 4)/18 = 41/18,

2) 9 7/9 - 41/18 = (9 * 9 + 7)/9 - 41/18 = 88/9 - 41/18 = (88 * 2)/18 - 41/18 = 176/18 - 41/18 = (176 - 41)/18 = 135/18 = 7,5,

Ответ. 4 2/7 - (7 1/3 - 4 2/7) = 1 5/21,

9 7/9 - (2 1/2 - 2/9) = 7.5.