Answer:
A) 
Step-by-step explanation:
The equation of a circle is
where
is the center and
is the radius. If
and
, then:

Therefore, the equation of the circle is 
You need to get rid of -6 by adding 6, you also need to add 6 to 18.
4x = 24
Now you need to get rid of the 4 attached to the variable, you do this by dividing 4 since it is multiplying, also dividing 4 and 24
x = 6
So the value of x is 6
Hope this helps! :)
No, that is not a factor to make it not a like term.
21d+.23x (d being per day) (x being every mile above 125)