Odpowiedź:
a)
2(x + 9) = 3(x + 6) - x
2x + 18 = 3x + 18 - x
2x + 18 = 2x + 18
2x - 2x = 18 - 18
0 = 0
Równanie tożsamościowe
x ∈ R
b)
- 2 = 2/5(3 - x) | * 5
- 10 = 2(3 - x)
- 10 = 6 - 2x
2x = 6 + 10 = 16
x = 16/2 = 8
c)
2 - x/3 + x = 2x + 3/5 | * 15
30 - 5x + 15x = 30x + 9
30 + 10x = 30x + 9
10x - 30x = 9 - 30
- 20x = - 21
20x = 21
x = 21/20