Multiple choice

Which of the following equations is not quadratic?

  1. (x + 1)2 = 2(x - 3)

  2. x2 - 2x = -2(3 - x)

  3. (x - 2)(x + 1) = (x - 1)(x + 3)

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A quadratic equation must have an x^2 term. In option C: (x-2)(x+1) = x^2 - x - 2, and (x-1)(x+3) = x^2 + 2x - 3. The x^2 terms cancel out, leaving a linear equation.

AI explanation

Expand the given expression (x - 2)(x + 1) = (x - 1)(x + 3) to get x^2 - x - 2 = x^2 + 2x - 3. Cancelling x^2 from both sides leaves -3x = -1, which simplifies to a linear equation instead of a quadratic one.

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