Answer:

Step-by-step explanation:
Factor using the perfect square rule.
:)
8 is the hundreds, 7 in the tens, and 3 in the ones
To solve for c, you need to get c onto one side of the equation, or make it c=__. So what I would do first is subtract a/b from both sides
a/b + c = d/c
-a/b
a/b - a/b + c = d/c - a/b
c = d/c-a/b
Take away 1 from either side so the equation becomes 63=3x then divide both sides by 3 so it becomes 21=x which is your answer (option A)