Odpowiedź:
a)
a₁ = 9
a₂ = x
a₃ = 37
a₃ - a₂ = a₂ - a₁
37 - x = x - 9
- x - x = - 9 - 37
- 2x = - 46
2x = 46
x = 46/2 = 23
b)
a₁ = 4
a₂ = x
a₃ = - 8
a₃ - a₂ = a₂ - a₁
- 8 - x = x - 4
- x - x = - 4 + 8
- 2x = 4
2x = - 4
x = - 4/2 = - 2
c)
a₁ = 1/2
a₂ = x
a₃ = 1/3
a₃ - a₂ = a₂ - a₁
1/3 - x = x - 1/2
- x - x = - 1/2 - 1/3
- 2x = - 3/6 - 2/6
- 2x = - 5/6
2x = 5/6
x = 5/6 : 2 = 5/6 * 1/2 = 5/12
