Answer:
a.(10,23)
b.(7,30)
e.(20,20)
Explanation:
We are given that
x=Width of garden
y=Length of garden
According to question
![x\geq 5](https://img.qammunity.org/2022/formulas/mathematics/high-school/8xti6hrj3lk8ovk98ld7bai03p4z2l5gog.png)
![y\geq 20](https://img.qammunity.org/2022/formulas/mathematics/high-school/v6061nfvwloqjlnmag19oa21kqmf8aw62c.png)
Perimeter of rectangle=
![2(x+y)](https://img.qammunity.org/2022/formulas/mathematics/high-school/xz8171zpie169wox628bni4on680jindi5.png)
Where x=Width of rectangle
y=Length of rectangle
Fencing used =
![2(x+y)](https://img.qammunity.org/2022/formulas/mathematics/high-school/xz8171zpie169wox628bni4on680jindi5.png)
![2(x+y)\leq 80](https://img.qammunity.org/2022/formulas/mathematics/high-school/kvuwux6es2eotuytbek3i6z2tleat2ttfc.png)
First we change inequality into equality
...(1)
...(2)
![2(x+y)=80](https://img.qammunity.org/2022/formulas/mathematics/high-school/my5gngyn1o5qcn9nrhijy5kq6xy1q2wpbi.png)
...(3)
Substitute x=0 in equation (3)
![y=40](https://img.qammunity.org/2022/formulas/mathematics/high-school/sjiei7e4ygju9aahn9rz4quyfsevhr7s5b.png)
Substitute y=0 in equation (3)
![x=40](https://img.qammunity.org/2022/formulas/mathematics/college/nn7y2uycpmg58bled5cv4qqsg5nzwny87y.png)
Substitute x=0 and y=0 in equation (3)
![2(x+y)\leq 80](https://img.qammunity.org/2022/formulas/mathematics/high-school/kvuwux6es2eotuytbek3i6z2tleat2ttfc.png)
![0\leq 80](https://img.qammunity.org/2022/formulas/mathematics/high-school/vejgmzdr3bxb4vgtmc9493jxu33wk74rq4.png)
It is true. Therefore, the shaded region below the line.
![0\geq 5](https://img.qammunity.org/2022/formulas/mathematics/high-school/awxlz535q73hxhnc4mmsb5yg9v98ewx6ld.png)
![0\geq 20](https://img.qammunity.org/2022/formulas/mathematics/high-school/e8tjcc8f2d8i0rt9wedexacbwjpyunpi8x.png)
These are false equation .Therefore, the shaded region above the line.
Substitute x=5 in equation (3)
![5+y=40](https://img.qammunity.org/2022/formulas/mathematics/high-school/vjexzmzuvcgdseae0zpyyddtvsrhq640ti.png)
![y=40-5=35](https://img.qammunity.org/2022/formulas/mathematics/high-school/65325bosbl9qru6zr3yxomwox8k6o0rs6d.png)
Substitute y=20 in equation (3)
![x+20=40](https://img.qammunity.org/2022/formulas/mathematics/high-school/pmv6c4rpazxcrdzflg5ltbj8yn7jil5fmw.png)
![x=40-20=20](https://img.qammunity.org/2022/formulas/mathematics/high-school/rqquqot25xe4q9e26etqrnhuj6fyhcp1pg.png)
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://img.qammunity.org/2022/formulas/mathematics/high-school/kvuwux6es2eotuytbek3i6z2tleat2ttfc.png)
![66\geq 80](https://img.qammunity.org/2022/formulas/mathematics/high-school/r7127gfi817jl4vcurpt3xvam6kz8bwcu9.png)
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<80](https://img.qammunity.org/2022/formulas/mathematics/high-school/vai7vopv4ip1563ny4je32ngmrn8smcp3t.png)
it satisfied all inequality.
Hence, it is a solution.
c.(18,25)
18>5
25>20
![2(18+25)=86>80](https://img.qammunity.org/2022/formulas/mathematics/high-school/23dw21vspu1kpecyia3ql6q1jesv5a5tlc.png)
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://img.qammunity.org/2022/formulas/mathematics/high-school/zyqc0591fb932ju1wxeby700iiwvayh5cs.png)
It does not satisfied third inequality
Hence, it is not a solution.
e.(20,20)
![2(20+20)=80](https://img.qammunity.org/2022/formulas/mathematics/high-school/lj3bxa8v2vvkxw4ibljuaihm8ikgmgbpvr.png)
20>5
20=20
it satisfied all inequality.
Hence, it is a solution.