Question

Find the lenght of DF. Figure is not drawn to scale.

Answer 1

According the graph DF is the addition of DE and EF, this can be used to obtain the value of x

`5+(3x+7)=(5x+6)`

solve the equation obtained for x

`\begin{gathered} 12+3x=6+5x \\ 12-6=5x-3x \\ 6=2x \\ x=(6)/(2) \\ x=3 \end{gathered}`

if x=3 replace in the equation of DF

`\begin{gathered} DF=5\cdot(3)+6 \\ DF=15+6 \\ DF=21 \end{gathered}`

DF is equal to 21 cm.