(7x + 2)-(x^2 + 5) in Z_10

7x-2-x-2-5-in-z-10-a-9x-2-7x-7-b-9x-2-6x-10

(7x + 2)-(x^2 + 5) in Z_10 =
A. 9x^2 + 7x + 7
B. 9x^2+ 6x + 10
C. 8x^2 + 7x + 6
D. None of the mentioned
Correct answer is A. 9x^2 + 7x + 7

(7x + 2) – (x^2 + 5) in Z_10 = 9x^2 + 7x +7. We can find this via basic polynomial arithmetic in Z_10.