(5ab-4a--5) its an online geometry class, ! i provided you 10 pts

(5ab-4a-8)-(9ab-5)
Ok just remember that the minus sign before the (9ab-5) is like a minus 1 so it changes the sign inside the bracket...
>>5ab-4a-8-9ab+5
>>-4ab-4a-3
I'm guessing you just have to leave it like that unless there are other parts to the question or whatever but that's that simplified as far as it can be!

1800×6.5%×30=b
b-1800=a

a) $1,710

b) $3,510