Question

Check whether the following is the quadratic equation: 

(x + 2)³ = 2x(x² - 1)

Answer 1

(x + 2)³ = 2x(x² - 1)

⇒ x³ + 3x²(2) + 3x(2)² + (2)³ = 2x³ - 2x

⇒ x³ + 6x² + 12x + 8 = 2x³ - 2x

⇒ x³ + 6x² + 12x + 8 - 2x³ + 2x = 0

⇒ -x³ + 6x² + 14x + 8 = 0

It is not of the form ax² + bx + c = 0.

Hence, the given equation is not a quadratic equation.