Answer:
a.(10,23)
b.(7,30)
e.(20,20)
Step-by-step explanation:
We are given that
x=Width of garden
y=Length of garden
According to question
![x\geq 5](https://tex.z-dn.net/?f=x%5Cgeq%205)
![y\geq 20](https://tex.z-dn.net/?f=y%5Cgeq%2020)
Perimeter of rectangle=![2(x+y)](https://tex.z-dn.net/?f=2%28x%2By%29)
Where x=Width of rectangle
y=Length of rectangle
Fencing used =![2(x+y)](https://tex.z-dn.net/?f=2%28x%2By%29)
![2(x+y)\leq 80](https://tex.z-dn.net/?f=2%28x%2By%29%5Cleq%2080)
First we change inequality into equality
...(1)
...(2)
![2(x+y)=80](https://tex.z-dn.net/?f=2%28x%2By%29%3D80)
...(3)
Substitute x=0 in equation (3)
![y=40](https://tex.z-dn.net/?f=y%3D40)
Substitute y=0 in equation (3)
![x=40](https://tex.z-dn.net/?f=x%3D40)
Substitute x=0 and y=0 in equation (3)
![2(x+y)\leq 80](https://tex.z-dn.net/?f=2%28x%2By%29%5Cleq%2080)
![0\leq 80](https://tex.z-dn.net/?f=0%5Cleq%2080)
It is true. Therefore, the shaded region below the line.
![0\geq 5](https://tex.z-dn.net/?f=0%5Cgeq%205)
![0\geq 20](https://tex.z-dn.net/?f=0%5Cgeq%2020)
These are false equation .Therefore, the shaded region above the line.
Substitute x=5 in equation (3)
![5+y=40](https://tex.z-dn.net/?f=5%2By%3D40)
![y=40-5=35](https://tex.z-dn.net/?f=y%3D40-5%3D35)
Substitute y=20 in equation (3)
![x+20=40](https://tex.z-dn.net/?f=x%2B20%3D40)
![x=40-20=20](https://tex.z-dn.net/?f=x%3D40-20%3D20)
Intersection point of equation (1) and (3) is (5,35) and intersect point of equation (2) and (3) is (20,20).
Now,
a.(10,23)
Substitute in
![2(x+y)\leq 80](https://tex.z-dn.net/?f=2%28x%2By%29%5Cleq%2080)
![66\geq 80](https://tex.z-dn.net/?f=66%5Cgeq%2080)
10>5 and 23>20
it satisfied all inequality.
Hence, it is a solution.
b.(7,30)
7>5
30>20
![2(7+30)=74](https://tex.z-dn.net/?f=2%287%2B30%29%3D74%3C80)
it satisfied all inequality.
Hence, it is a solution.
c.(18,25)
18>5
25>20
![2(18+25)=86>80](https://tex.z-dn.net/?f=2%2818%2B25%29%3D86%3E80)
It does not satisfied third inequality
Hence, it is not a solution.
d.(8,35)
8>5
35>20
![2(8+35)=86>80](https://tex.z-dn.net/?f=2%288%2B35%29%3D86%3E80)
It does not satisfied third inequality
Hence, it is not a solution.
e.(20,20)
![2(20+20)=80](https://tex.z-dn.net/?f=2%2820%2B20%29%3D80)
20>5
20=20
it satisfied all inequality.
Hence, it is a solution.