Which equation represents a quadratic function?
answer choices:

a. f(x)={−3, ifx > 25, ifx ≤2

b. f(x)=(x+1)2−2

c. f(x)=||x−9||

d. f(x)=4(x+2)

A quadratic function would be option number B. As this has a variable raised to the power 2. In this case it would be f(X) = (X+1)^2 - 2. This is in a different form of what the quadratic typically will be found in, which is in the form of Ax^2 + Bx + C.