5a^2-2ab+6a-7ab-6a^2-6a при a=5, b=- 1/9

Question

5a^2-2ab+6a-7ab-6a^2-6a при a=5, b=- 1/9

Answer 1

5а^2-2ab+0-7ab-6a^2
5a^2-2ab-7ab-6a^2
-a^2-2ab-7ab
-a^2 - 9ab
-5^2 - 9*5*(-1/9)
ответ 30