SOLUTION: A rectangular playground is 420 sq.m. If its length is increases by 7m and breadth is decreased by 5 meters, the area remains the same. Find the length and breadth of the playgroun

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: A rectangular playground is 420 sq.m. If its length is increases by 7m and breadth is decreased by 5 meters, the area remains the same. Find the length and breadth of the playgroun      Log On


   

Question 981935: A rectangular playground is 420 sq.m. If its length is increases by 7m and breadth is decreased by 5 meters, the area remains the same. Find the length and breadth of the playground?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
let length be x
area = l*b
breadth = 420/x



(x+7)(420-5x) = 420x

420x-5x%5E2%2B420%2A7-35x=420x
-5x%5E2-35x%2B420%2A7=0
/-5
x%5E2%2B7x-588=0

(x-28)(x+21)=0
x=28 OR -21
length = 28m & breadth = 21 m