Which of the following is not a quadratic equation?


A quadratic equation is represented by the form,

ax2 + bx + c = 0, a ≠ 0


A. Given, 2(x - 1)2 = 4x2 - 2x + 1


2(x2 - 2x + 1) = 4x2 - 2x + 1


2x2 + 2x – 1 = 0


which is a quadratic equation.


B. Given, 2x - x2 = x2 + 5


2x2 - 2x + 5 = 0


which is a quadratic equation.


C. Given, = 3x2 – 5x


= 3x2 – 5x



which is a quadratic equation.


D. Given, (x2 + 2x)2 = x4 + 3 + 4x2


x4 + 4x3 + 4x2 = x4 + 3 + 4x2


4x3 – 3 = 0


which is a cubic equation and not a quadratic equation.

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