Answer:
![(1,7)](https://img.qammunity.org/2022/formulas/mathematics/college/9zb7xzl3f11wu2pb17pqjjpp2luc0drtq0.png)
Explanation:
Given
![x + 3y = 22](https://img.qammunity.org/2022/formulas/mathematics/college/6bgpbllua9upihpwys0ont4mplyqoizidt.png)
Solving (a): The possible coordinates
We have:
![(x,y) = (-2,8)](https://img.qammunity.org/2022/formulas/mathematics/college/k018cmsij9vfa2e36idjrr553kzc2o3goj.png)
This gives:
![x + 3y = 22 \to -2 + 3 * 8](https://img.qammunity.org/2022/formulas/mathematics/college/nrf4itiim16gt0u7c1ydhj9tl6624a7lo4.png)
![x + 3y = 22 \to -2 + 24](https://img.qammunity.org/2022/formulas/mathematics/college/etnvw1dhxbl721dbcp09jzf4v8xijguzl7.png)
![x + 3y = 22 \to 22](https://img.qammunity.org/2022/formulas/mathematics/college/i5csqjl8sxgdqfct40n69x17ni8bb81ejq.png)
(-2,8) is a point on the grid
![(x,y) = (7,5)](https://img.qammunity.org/2022/formulas/mathematics/college/ye7bay2rrpzb7kqcqznrp72ynfneiickf5.png)
This gives:
![x + 3y = 22 \to 7 + 3 * 5](https://img.qammunity.org/2022/formulas/mathematics/college/zhjsp7qk7wso6yfo979thmc3u0pen7xng4.png)
![x + 3y = 22 \to 7 + 15](https://img.qammunity.org/2022/formulas/mathematics/college/16ps3ip3xodax3e0831ktn7cyscu6epnsy.png)
![x + 3y = 22 \to 22](https://img.qammunity.org/2022/formulas/mathematics/college/i5csqjl8sxgdqfct40n69x17ni8bb81ejq.png)
(7,5) is a point on the grid
![(x,y) = (-5,5)](https://img.qammunity.org/2022/formulas/mathematics/college/zjaeko68p2rsemle6mrfxv5u5qi2cu5u69.png)
This gives:
![x + 3y = 22 \to -5 + 3 * 5](https://img.qammunity.org/2022/formulas/mathematics/college/42cvjmy79l5hxc46ld76o0vxr7g0y8u9ra.png)
![x + 3y = 22 \to -5 + 15](https://img.qammunity.org/2022/formulas/mathematics/college/8ddfw1zsfwvp11whmzis0i9wgql9vjlrsv.png)
![x + 3y = 22 \to 10](https://img.qammunity.org/2022/formulas/mathematics/college/eabaun9hnifxz5f899kphznsrs58c3cwjk.png)
(-5,5) is a not point on the grid
![(x,y) = (1,3)](https://img.qammunity.org/2022/formulas/mathematics/college/i0myq56zythmjil3mbzpm9zyef6pzrteas.png)
This gives:
![x + 3y = 22 \to 1 + 3 * 3](https://img.qammunity.org/2022/formulas/mathematics/college/yxg2vm9ki9pdegps4r0804lek9lmfixcg8.png)
![x + 3y = 22 \to 1 + 9](https://img.qammunity.org/2022/formulas/mathematics/college/3ty1v9k7e5ocn340o6enlfh2qgpg0wjzma.png)
![x + 3y = 22 \to 10](https://img.qammunity.org/2022/formulas/mathematics/college/eabaun9hnifxz5f899kphznsrs58c3cwjk.png)
(1,3) is a not point on the grid
![(x,y) = (1,7)](https://img.qammunity.org/2022/formulas/mathematics/college/sqfq8qdkwu7ikj96nbe74877x1pnumpjg1.png)
This gives:
![x + 3y = 22 \to 1 + 3 * 7](https://img.qammunity.org/2022/formulas/mathematics/college/6k5dh8h80umkk3k886c9rhih53twoo62o6.png)
![x + 3y = 22 \to 1 + 21](https://img.qammunity.org/2022/formulas/mathematics/college/7iixb25rlr3hz63rchol0tvzeofwk9ehql.png)
![x + 3y = 22 \to 22](https://img.qammunity.org/2022/formulas/mathematics/college/i5csqjl8sxgdqfct40n69x17ni8bb81ejq.png)
(1,7) is a point on the grid
So, we plot the following on the grid
![(1,7)](https://img.qammunity.org/2022/formulas/mathematics/college/9zb7xzl3f11wu2pb17pqjjpp2luc0drtq0.png)
See attachment