Відповідь:

Покрокове пояснення:

(х - (9 * 3/7)) + (5 * 1/3) = 6 5/14

(х - (27/7)) + (35/21) = 6 5/14

21 * (х - 27/7) + 21 * (35/21) = 21 * (6 5/14

21x - 9 * 3 + 35 = 90 10/14

90 + 10/14 = 90 + 5/7 = 630/7 + 5/7 = 635/7

21x - 27 + 35 = 635/7

21x + 8 = 635/7

21x = 579/7

x = 579/147

x = 3 * (193/49)

x = 12