n = 10, so the first option is correct. the work to prove this is below:
6n - 1 = 5n + 9 (add 1)
6n = 5n + 10 (subtract 5n)
n = 10
**** Now find the measure of the sides by plugging in what n equals. ****
CD = 4n + 2
CD = 4(10) + 2
CD = 40 + 2
CD = 42
********** Since this is a parallelogram, CD and FE have to be equal, so since FE = CD, and CD = 42, FE also has to equal 42. This makes the fourth statement true. *********************************************************************
Now find the measure of the other two sides.
CF = 6n - 1
6(10) - 1
60 - 1
CF = 59
Since CF = 59, DE also has to eqaul 59. This means that the third statement is also true.
Your answers should be:
n = 10
CF = 59
FE = 42