a)3(1-2x)-5(3-x)-6(3x-4)=83
3-6x-15+5x-18x+24=83
-19x+12=83
-19x=83-12
-19x=71
x=71/(-19)
x=-3 14/19
b)23-3(B+1)+5(6B-7)-7(3B-1)=0
23-3B+3+30B-35-21B+7=0
6B-8=0
6B=8
B=8/6
B=1 1/3
в)2m+m(3-(m+1))=m(2-m)+12
2m+3m-m^2-m=2m-m^2+12
2m=12
m=6
Б)7+3(-k-3(k+5))=5(7-2k)+k
7-3k+9k-45=35-10k+k
15k=73
k=73/15
k=4 13/15