Odpowiedź:
a. 21 + 5x = 41
21+ 5x - 21 = 41 - 21
5x = 41 - 21
5x = 20
x = 4
b. 4y - 5,4 = -24,6 x
4y = -24,6 x + 5,4
4y + 24,6 = 5,4
40y + 246x = 54
20y + 123x =27
123x + 20y = 27
c. 6 - 5 - 4x = 7
1 - 4x = 7
-4x = 7 - 1
-4x = 6
[tex]x=-\frac{3}{2} =-1\frac{1}{2}[/tex]