The c+5 should represent the five more cds that he has thats more than julias
Let's call Tacos t and Enchiladas e.
Lily paid $9 for 2t and 3e
Alex paid $12.50 for 3t and 4e.
Thus the equations would be.

Answer:
I THINK its the last one (8 root 10 to the power of 3x)
Step-by-step explanation:
A square root is the same thing as raising something to the 1/2. So the expression we have is (10^1/2)^3/4x.
Due to exponent rules we can multiply to get
10^3/8x which is the same thing as 10^3x/8
The 8 goes to the root and the 3x becomes the exponent