This one can't be solved as you would just get 1=1, which isn't too handy. Are you sure you copied it right?
3.
5(f+2)=2(3-f)
5f+10=6-2f
7f=-4
f=-4/7
4.
3(d-8)=3d
3d-24=3d?
Again, this one looks like it might not have been copied correctly as it is impossible for 3(d-8) to be the same as 3d. Think about it: if you divided both sides by 3 then you would get d-8=d and that wouldn't be possible :P
Answers & Comments
Verified answer
1.
2(7+3t)=-t
14+6t=-t
14+7t=0
7t=-14
t=-2
2.
3(a+1)-5=3a-2
3a+3-5=3a-2
3a-2=3a-2
This one can't be solved as you would just get 1=1, which isn't too handy. Are you sure you copied it right?
3.
5(f+2)=2(3-f)
5f+10=6-2f
7f=-4
f=-4/7
4.
3(d-8)=3d
3d-24=3d?
Again, this one looks like it might not have been copied correctly as it is impossible for 3(d-8) to be the same as 3d. Think about it: if you divided both sides by 3 then you would get d-8=d and that wouldn't be possible :P