<u>Solution:</u>
- 3⁸¹ = 3⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹ ⁺ ⁹
- 3⁸¹ = 3⁹ x 3⁹ x 3⁹ x 3⁹ x 3⁹ x 3⁹ x 3⁹ x 3⁹ x 3⁹
- 3⁹ = 19683 <u>[Using Calculator]</u>
This means that the Unit digit of 19683 is 3. For each number, multiply the unit's digit of 3⁹.
- 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3 x 3
- => 19683
- => <u>Unit digit of 3⁸¹ = 3</u>
Option A is correct.
It's as it is said

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Your question is unclear.
Answer:
Therefore the answer is 7
The answer is A. x = 8. All the points on the line are ( 8 , y ).