<h2>Answer:</h2>
The equation that is used to model the length of ladder in terms of x is:
We can model this problem with the help of a right angled triangle whose hypotenuse is 13 meters and the other two legs are x meters and (x-7) meters.
where x is the distance between the top of the ladder and the ground.
and (x-7) is the distance between the foot of the ladder and the wall.
Hence, using Pythagorean Theorem we have:
Hence, the answer is: