Question

Which of the following is a quadratic equation?

Options

• `x^2 - 3sqrt(x) + 2 = 0`

• `x + 1/x = x^2`

• `x^2 + 1/x^2 = 5`

• `2x^2 - 5x = (x - 1)^2`

Answer 1

2x² – 5x = (x – 1)²

Explanation: 

A quadratic equation is the equation with degree 2. 

∵ 2x² – 5x = (x – 1)² 

⇒ 2x² – 5x = x² – 2x + 1 

⇒ 2x² – 5x – x² + 2x – 1 = 0 

⇒ x² – 3x – 1 = 0, which is a quadratic equation