For each pair of structures, determine whether they represent different compounds or a single compound.

I found a similar question, so I think this can be taken as our problem because you seem to forgot including the picture. So, for letter a, the answer is: they represent different compounds. As you can notice, the CH₂CH₃ and CH₃ are both on the top side for the left figure, while the CH₃ and CH₃ are on the top side of the right figure. They are cis-trans isomers. The left figure is trans-2-pentene while the left figure is cis-2-pentene. 

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer