(980:n) * 18 - 84 = 276
(980:n) * 18 = 276 +84
(980:n)* 18 = 360
980 : n = 360:18
980 : n = 20
n = 980 : 20
n = 49
96 + (80 - x) : 14 = 100
(80 - x) : 14 = 100 - 96
(80- x) : 14 = 4
80 - x = 14 * 4
80 - x = 56
x = 80 - 56
x = 24
ПРОВЕРКУ СДЕЛАЕШЬ САМА.