Odpowiedź:
a)
20 + 5x = 40
5x = 40 - 20
5x = 20 /: 5
x = 4
Sprawdzenie:
20 + 5 • 4 = 40
20 + 20 = 40
40 = 40
L = P
b)
9x - 3 = 2x + 5
9x - 2x = 5 + 3
7x = 8 /: 7
x = 8/7
Sprawdzenie:
9 • 8/7 - 3 = 2 • 8/7 + 5
72/7 - 3 = 16/7 + 5
72/7 - 21/7 = 16/7 + 35/7
51/7 = 51/7
L = P
