Select all of the following functions that are quadratic.

A function is quadratic when, after solving for y and simplifying, its highest power of x is 2. Choice A is y = 2x², so it is quadratic. In choice D, subtracting 3x gives y = 2x² − 3x − 8, which is also quadratic. Choice C and choice E simplify to linear expressions in x, and choice B does not define y.

AI-written and checked against the verified answer.