Answer:
Everything should simplify down to -9a-3 (your answer)
Explanation:
Distributive property is basically multiplying the outside number into the inside parenthesis (). Basically #(a)--->#a or #(a+b)---> #a+#b
Since you're not ask to solve for anything but simplify, just multiply 3 to -3a and -1.....
so 3*-3a is -9a and 3*-1 is -3 and you have 3(-3a-1)= -9a-3