We see that CF and DE are parallel to each other, which means that they had the same length with each other, so: 6n-1=5n+9 Subtract 5n for both side 6n-1-5n=5n+9-5n n-1=9 Add 1 for both side n-1+1=9+1 n=10 CF= 6n-1 =6(10)-1 =60-1 =59 DE= 5n+9 =5(10)+9 =50+9 =59 CD/FE: 4n+2 =4(10)+2 =42 True/False: n=10 True n=7 False CF=59 True FE=42 True CD=30 False. As a result, n=10;CF=59; and FE=42 is your final answer. Hope it help!