1) 18=x/(-3), x=-3×18=-54.
2) b (x is the number of weeks at 5 pounds per week)
3) 8(2x-1)-5x=25, 16x-8-5x=25, 11x=33, x=3.
4) -2/(3(x+2))=12, 3(x+2)/(-2)=1/12, 3(x+2)=-2/12=-⅙, 3x+6=-⅙, 3x=-6-⅙=-6⅙=-37/6, x=-37/18.
5) x+3=x-6 has no solution because it's a false statement: 3=-6 is false.
6) They're all equivalent.
7) b (19-5=3m-m, 14=2m, m=14/2=7).