Answer is 4/7
You divide the length of C'D' over the length of CD
C'D'/CD = 8/14 = 4/7
The scale factor is smaller than 1, so C'D' is shorter than CD
Both 27 and 45 have the greatest common factor of 9, so divide the numerator and the denominator by 9 to get the simplest form.
27/45 = 3/5
3/5 is the simplest ratio
-54-7r=10+25r
-7r-25r=10+54
-32r=64
r=64/-32
r=-2