zad. 3
a) 2*(a+5)=2a+10
b) -3*(4-2b)= -12+6b
c) (7-c)*5= 35-5c
d) (4d+8):4= d+8
zad. 4
a) 9+(2-6a)= 9+2-6a=11-6a
b) -(6b+1)=-6b-1
c) (9+f)-(3f-4)=9+f -3f+4=13-2f
