Odpowiedź:
Zad.3
a) 5x+7 = 22 |-7
5x = 15 |:5
x = 3
b) 5x-5 = x+7
5x-x = 7+5
4x = 12 |:4
c) 2(x+4) = x-7
2x+8 = x-7
2x-x = -7-8
1x = -15
x = -15
Zad.4
x+x-7 = 85
2x-7 = 85
2x = 85+7
2x = 92 |:2
x = 46 - pierwsza liczba
46-7 = 39 - druga liczba
Zad.5
x+x+1+x+2 = 138
3x+3 = 138
3x = 138-3
3x = 135 |:3
x = 45
Te liczby to 45,46,47
