SOLUTION: The width of a rectangle is 2 ft less than the length. the area is 8 ft^2. Find the length and the width. PLEASE HELP!!!

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: The width of a rectangle is 2 ft less than the length. the area is 8 ft^2. Find the length and the width. PLEASE HELP!!!      Log On


   

Question 155598: The width of a rectangle is 2 ft less than the length. the area is 8 ft^2. Find the length and the width.
PLEASE HELP!!!
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!
Remember: For rectangle,
Area=Length%2AWidth----------------------------> working eqn
Given:
L=unknown=x
W=x-2ft
A=8ft%5E2
Substitute, 8=x%2A%28x-2%29
8=x%5E2-2x ------> x%5E2-2x-8=0
BY QUADRATIC: a=1, b=-2, & c=-8
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x=%28-%28-2%29%2B-sqrt%28-2%5E2-4%2A1%2A-8%29%29%2F%282%2A1%29
x=%28%2B2%2B-sqrt%284%2B32%29%29%2F2
x=%282%2B-sqrt%2836%29%29%2F2
x=%282%2B-6%29%2F2---> 2 values %282%2B6%29%2F2=8%2F2=4,%282-6%29%2F2=-4%2F2=-2
USED x=4ft ----------------> LENGTH
4-2=2ft -----------------> WIDTH
In doubt? Go back working eqn:
8ft%5E2=%284ft%29%282ft%29
8ft%5E2=8ft%5E2
Thank you,
Jojo