SOLUTION: the length of a rectangle is 7 meters more than four times its width. If the area o the rectangle is 650 square meters, find the length and the width

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: the length of a rectangle is 7 meters more than four times its width. If the area o the rectangle is 650 square meters, find the length and the width       Log On


   

Question 1026848: the length of a rectangle is 7 meters more than four times its width. If the area o the rectangle is 650 square meters, find the length and the width





Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
width be x
length = 4x+7
Area = 650 m^2
Area = L *W
x(4x+7) =650
4x^2+7x-650=0
a= 4 , b= 7 , c= -650

b^2-4ac= 49 + 10400
b^2-4ac= 10449
%09sqrt%28%0910449%09%29=%09102.22%09
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=( -7 + 102.22 )/ 8
x1= 11.90
x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x2=( -7 -102.22 ) / 8
x2= -13.65

ignore negative
width = 11.8 m
length = 4*11.9 +7
=54.6 m