в) 5 ⋅ (90 - x ⋅ 3) + 35 = 350
5 ⋅ (90 - x ⋅ 3) = 350 - 35
5 ⋅ (90 - x ⋅ 3) = 315
90 - x ⋅ 3 = 315 : 5
90 - x ⋅ 3 = 63
x ⋅ 3 = 90 - 63
x ⋅ 3 = 27
x = 27 : 3
x = 9
г) 320 – (b ⋅ 4 + 120) : 5 = 240
– (b ⋅ 4 + 120) : 5 = 240 - 320
– (b ⋅ 4 + 120) : 5 = -80
(b ⋅ 4 + 120) : 5 = 80
b ⋅ 4 + 120 = 80 ⋅ 5
b ⋅ 4 + 120 = 400
b ⋅ 4 = 400 - 120
b ⋅ 4 = 280
b = 280 : 4
b = 70
Ответ: в) x = 9; г) b = 70