Answer:
5.69 feet by 19.69 feet
Step-by-step explanation:
Given : A gardener wants to create a rectangular vegetable garden in a backyard. He wants it to have a total area of 112 square feet, and it should be 14 feet longer than it is wide.
Let x be the breadth of the rectangular vegetable garden
So, length of the rectangular vegetable garden = ( x + 14 ) feet
To find: dimensions that a gardener should use for the vegetable garden
Solution :
We know that area of the rectangle is equal to length ( l ) × breadth ( b )
Area of the rectangular garden = 112 square feet
According to question,
![x(x+14)=112\Rightarrow x^2+14x-112=0](https://tex.z-dn.net/?f=x%28x%2B14%29%3D112%5CRightarrow%20x%5E2%2B14x-112%3D0)
In order to find roots, use quadratic formula which states that for equation
, roots are ![\frac{-b\pm \sqrt{b^2-4ac}}{2a}](https://tex.z-dn.net/?f=%5Cfrac%7B-b%5Cpm%20%5Csqrt%7Bb%5E2-4ac%7D%7D%7B2a%7D)
Therefore, for equation
, roots are ![\frac{-14\pm \sqrt{196+448}}{2}=\frac{-14\pm \sqrt{644}}{2}](https://tex.z-dn.net/?f=%5Cfrac%7B-14%5Cpm%20%5Csqrt%7B196%2B448%7D%7D%7B2%7D%3D%5Cfrac%7B-14%5Cpm%20%5Csqrt%7B644%7D%7D%7B2%7D)
Being a dimension, breadth can not be negative, so x =
is rejected
Therefore,
![x=\frac{-14+ \sqrt{644}}{2}=5.69\Rightarrow l = x+14=5.69+14=19.69](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B-14%2B%20%5Csqrt%7B644%7D%7D%7B2%7D%3D5.69%5CRightarrow%20l%20%3D%20x%2B14%3D5.69%2B14%3D19.69)
So, length = 19.69 feet and breadth = 5.69 feet