SOLUTION: Question 7) If the area of the given rectangle is 77cm2, find its length and breadth Length= x+4 Breadth= x

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Question 7) If the area of the given rectangle is 77cm2, find its length and breadth Length= x+4 Breadth= x      Log On


   

Question 60969: Question 7) If the area of the given rectangle is 77cm2, find its length and breadth Length= x+4 Breadth= x
Answer by joyofmath(189) About Me  (Show Source):
You can put this solution on YOUR website!
Length = x+4
Breadth = x
Area = Length+x+Breadth+=+x%28x%2B4%29+=+77
So, x%5E2%2B4x+=+77
Or x%5E2%2B4x-77+=+0
This is a quadratic equation which factors into %28x-7%29%28x%2B11%29=0
So, x=7 and x=-11 are possible values.
But, x can't be negative, so x=7.
We verify this answer by multiplying Length = 7 by Breadth = 7+4=11 and we do get 77.