SOLUTION: The length of a rectangular gym is 8 meters less than 3 times it's width. Find the dimensions is the area of the gym is 336 square meters. ^^ I do not understand how to set u

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The length of a rectangular gym is 8 meters less than 3 times it's width. Find the dimensions is the area of the gym is 336 square meters. ^^ I do not understand how to set u      Log On


   

Question 449819: The length of a rectangular gym is 8 meters less than 3 times it's width. Find the dimensions is the area of the gym is 336 square meters.

^^ I do not understand how to set up the equation.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
width=x
length = 3x-8
Area = L*W
x(3x-8)=336
3x^2-8x=336
3x^2-8x-336=0
Find the roots of the equation by quadratic formula

a= 3 ,b= -8 ,c= -336

b^2-4ac=64-4032
b^2-4ac=4096
sqrt%284096%29=64
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=(8+64)/6
x1=12
x2=(8-64)/6
x2= -9.33
Ignore negative value
width = 12
length = 3x-8===>28