Which of the following is not a quadratic equation

Which of the following is not a quadratic equation?

1. $ 2(x −1)^2 = 4x^2 − 2x + 1 $
2. $ 2x − x^2 = x^2 + 5 $ 
3. $ (\sqrt{2}x + \sqrt{3})^2 + x^2 = 3x^2 -5x $
4. $ (x^2 + 2x)^2 = x^4 + 3 + 4x^3 $

Answer

C. $ (\sqrt{2}x + \sqrt{3})^2 + x^2 = 3x^2 -5x $

• Exam Year: 2023