Hey there!
Usually in equations, to clear the denominator, we multiply both sides by it. In our case here, the denominator is one, so when we multiply both sides by one we get the same thing. We can just remove the denominator:
c - 7 = 3
Using the property of equality which states that you do the same thing to both sides and get an equal equation, we can add seven to both sides in an effort to isolate x to get:
c = 10
To check, we plug in 10 for c:
10 - 7 = 3
3 = 3 (check!)
Hope this helps!