Answer:
The length of EF = x = 18 cm
Option A is correct.
Step-by-step explanation:
Ware given perimeter of triangle = 97 cm
We need to find length of EF = x = ?
The length of EG = x+7
The length of EF = x
The length of GF = 3x
The formula used is: 
Putting values and finding x i.e length of EF

So, value of x=18 cm
The length of EF = x = 18 cm
Option A is correct.
Answer:


Step-by-step explanation:
Write the system


Solve by Elimination.
multiply the second equation by -3.


Add the Equations.


Plug this back in one of the equations.


<4 and <2 corresponding angles
<6 and <3 alternate interior angles
<4 and <5 alternate exterior angles
<6 and <7 interior angles on the same side of transversal