Question

Which of the following equations represents a quadratic function?

Answer 1

The answer is b. y=3x^2-5x+9

The general formula for quadratic function is:
y = ax² + bx + c 

Among all choices only b. is correct:
y = ax² + bx + c 
y = 3x² - 5x + 9 

Answer 2

a. x=y^2-2y+4 & b. y=3x^2-5x+9

or just b. y=3x^2-5x+9 (if you can only choose one answer)