Choose the correct answer from the given four options : Which of the following is a quadratic equation?

Question

KollegeApply · Accepted Answer

(x – 2) (x + 1) = (x – 1) (x – 3) ⇒ x2 + x – 2x – 2 = x2 – 3x – x + 3 ⇒ 3x + x – 2x + x = 3 + 2 ⇒ 3x = 5 It is not a quadratic equation (x + 2)3 = 2x(x2 - 1) x3 + 6x2 + 12x + 8 = 2x3 – 2x x3 + 6x2 + 12x + 8 – 2x3 + 2x = 0 –x3 + 6x2 + 14x + 8 = 0 It is not a quadratic equation. x2 + 3x + 1 = (x – 2)2 x2 + 3x + 1 = x2 – 4x + 4 3x + 1 + 4x – 4 = 0 ⇒ 7x – 3 = 0 It is not a quadratic equation. 8(x – 2)3 = (2x – 1)3 + 3 8(x3 – 6x2 + 12x - 8) = 8x3 – 12x2 + 6x – 1+ 3 8x3 – 48x2 + 96x – 64 – 8x3 + 12x2 – 6x + 1 – 3 = 0 –36x2 + 90x – 66 = 0 It is a quadratic equation.

AChoose Your Answer