Question

If KN=29, what is CN?

Answer 1

KN has length  2x + 10 + 4x + 1 = 29 units, so

6x + 11 = 29, or 6x = 18 and x = 3.

Then CN = 4x + 1 = 4(3) + 1 = 13 units (answer)

Answer 2

To find the answer you need to identify what x is.
To find the x first you need to make the equation 6x+11=29.
You then subtract 11 from each side which cancels out the 11 and makes the 29 18. 
You then divide the entire equation by 6 to get the answer x=3. 
You then input x for the CN line equation.
4(3)+1
Thus, your answer should be 13 (D)