Midpoint solve with step by step

Step-by-step explanation:

If D is the midpoint of CE, that means that D is exactly in the middle of CE, splitting it in 2 equal length segments.  That means that CD = DE in length.  If CD = 9x - 7 and DE = 3x + 17, then

9x - 7 = 3x + 17 and

6x = 24 so

x = 4

Now we'll sub 4 in for x in either expression for half the length.  If DE = 3x + 17, then when we sub in 4 for x: 3(4) + 17 = 29.  That means that half the length of CE is 29.  Double that and you'll get that the length of CE = 58