What is the answer to 21-9f=-20(f-6)

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

Apositive number a or the same number a increased by 50% and then decreased by 50% of the result?

Student price tickets to a movie are $1 and non student tickets are $2. 350 tickets are sold and the total amount made is $450. how many non student tickets were sold ? a) 100 b) 150 c) 200 d)250