I can't figure out these 2 questions from the applications section.

P(x) = and x-3 is a factor of P(x)

Q (x) = and Q(-2) = -2

Find the values of a and b

Second Question:A tennis ball thrown into the air follows a curved path described by the equation

H is height, t is seconds

What was the greatest height the ball reached during its flight.

Looking for explanations rather than answers.

Thanks.