ANSWER
A) 4x - 7 = 21
Step-by-step explanation
We have that 21 goats were shown in the county fair.
The number of goats is 7 less than 4 times the number of horses.
Let the number of horses be h.
Therefore, 7 less than 4 times the number of horses is:
4 * x - 7
= 4x - 7
We have this is equal to the number of goats. Therefore, the equation that can be used to solve the problem is:
4x - 7 = 21