A)
Koty = x
Psy = 2x
Rybki = 3x
Wszystko = 12
x + 2x + 3x = 12
6x = 12 |:6
x = 2
2x = 4
3x = 6
Odp: Pani Brygida ma 2 koty, 4 psy i 6 rybek
B)
Ewa = x
Marek = x + 3
Adam = 3x
Ewa za 5 lat = x + 5
Marek za 5 lat = x + 3 + 5
Adam za 5 lat = 3x + 5
x + 5 + x + 3 + 5 = 3x + 5
2x + 13 = 3x + 5 |-3x
-x + 13 = 5 |-13
-x = -8 |:(-1)
x = 8
x + 3 = 11
3x = 24
Odp: Ewa ma 8 lat, Marek 11, a Adam 24
Pozdrawiam~Haruqe