Найди устно корни уравнений: 2 + b = 30 5 • m = 55 70 - c = 14 60 : d = 5 a • 40 = 120

Решение:

• 2 + b = 30
  b = 30 - 2
  b = 28
• 5 ⋅ m = 55
  m = 55 : 5
  m = 11
• 70 - c = 14
  c = 70 - 14
  c = 56
• 60 : d = 5
  d = 60 : 5
  d = 12
• a ⋅ 40 = 120
  a = 120 : 40
  a = 3

Дополнительные уравнения:

• t - 39 = 8
  t = 8 + 39
  t = 47
• 42 : x = 14
  x = 42 : 14
  x = 3
• k : 16 = 4
  k = 16 ⋅ 4
  k = 64
• 34 - y = 19
  y = 34 - 19
  y = 15
• n + 320 = 410
  n = 410 - 320
  n = 90