Which represents a quadratic function?

A; f(x) = −8x^3 − 16x^2 − 4x

B; f(x) = 3/4 x^2 + 2x − 5

C; f(x) = 4/x^2 - 2x +1

D; f(x) = 0x^2 − 9x + 7
WILL MARK BRAINLIEST!

What expression is equivalent to 42x-56y

Fanny mendelssohn manages all the magazines and paperback books at a local grocery store. she prices many paperbacks to sell at $7.99. the cost to the store is $5.29. what is the markup rate on a paperback book, based on its cost?

Which of the choices shown could be used to prove that aacp=abcp ?