Question

A ladder (line segment AC in the diagram) is leaning against a wall. The distance between the foot of the ladder and the wall (BC) is 7 meters less than the distance between the top of the ladder and the ground (AB). A-Create an equation that models the length of the ladder (l) in terms of x, which is the length in meters of AB. B-If the length of the ladder is 13 meters, use the equation you wrote to find the distance between the ground and the top of the ladder (AB).

Answer 1

Greetings from Brasil...

a)

Let's just use Pythagoras

L² = X² + (X - 7)²

L = √(2X² - 14X + 49)

b)

If L = 13, then what is the value of X ???

L² = 2X² - 14X + 49

2X² - 14X - 120 = 0

X = 12  or  X = - 5

(The distance cannot be negative, so X = 12)