Respuesta :

jessiluvsdance

Answer:

the length of side DF is 19

Step-by-step explanation:

you first need to find what x=

sides  AB=DF    AC=DE    BC=FE

so we can say that 3x+1=19

3x+1=19

-1        -1

3x=18

÷ by 3

x=6

then DF os 2x+7

so 2(6)+7

12+7=19