Select all of the following that are quadratic functions

Any function is quadratic whose highest degree is 2, it means we should have x² or y² as the only highest degree term.

Note: - We do not consider x³ or y³ because it will make cubic equations.

So from the given options, we can select followings:-

x = 3y² - 6y + 5

y + 3 = - 2x² + 5

y = 2x² - 8x + 6

y = 5·x· (x + 9) - 8 = 5x² + 45x - 8

y - 2x² = 3x - 2x² + 4

B, C, F

Step-by-step explanation:

It's the right answer.