Need help with question 3. Anything is appreciated thank you:)

Which of the following constants can be added to x2 - 3x to form a perfect square trinomial?

Acompany that makes? hair-care products had 5000 people try a new shampoo. of the 5000 ? people, 35 had a mild allergic reaction. what percent of the people had a mild allergic? reaction?

The table below shows the number of free throw shots attempted and the number of shots made for the five starting players on the basketball team during practice. each player's goal is to make 80% of her shots.