14. Реши уравнения с комментированием и сделай проверку:

a) (4¹/₉ - a) + 8⁵/₉ = 9²/₉
4¹/₉ - a = 9²/₉ - 8⁵/₉
4¹/₉ - a = ¹¹/₉
a = 4¹/₉ - 1²/₉ = 3⁸/₉
б) 5³/₇ - (b - 2¹/₇) = 2⁴/₇
b - 2¹/₇ = 5³/₇ - 2⁴/₇
b - 2¹/₇ = 2⁴/₇
b = 2⁴/₇ + 2¹/₇ = 4⁵/₇
в) 500 - 400 : (x + 43) = 495
400 : (x + 43) = 500 - 495
400 : (x + 43) = 5
x + 43 = 400 : 5
x + 43 = 80
x = 80 - 43 = 37
г) (270 : y - 12) * 70 = 1260
270 : y - 12 = 1260 : 70
270 : y - 12 = 18
270 : y = 18 + 12
270 : y = 30
y = 270 : 30 = 9