Answer: -81a^2 + 27a + 10
Step-by-step explanation: We can do this question by using FOIL (first, outer, inner, last)
(-9a-2)(9a-5)
First, multiply the first two terms in the parentheses
-9a times 9a is -81a^2
Second, multiply the outer terms
-9a times -5 is 45a
Third, multiply the inner terms
-2 times 9a is -18a
And lastly, multiply the last terms
-2 times -5 is 10
After doing this we end up with -81a^2 + 45a - 18a + 10 = -81a^2 + 27a + 10