Check whether the following are quadratic equation.(x – 3) (2x + 1)

1.	Check whether the following are quadratic equation.(x – 3) (2x + 1) = x(x + 5)
Answer» Given: (x – 3) (2x + 1) = x(x + 5) ⇒ x (2x + 1) – 3 (2x + 1) = x . x + 5 . x ⇒ 2x² + x – 6x – 3 = x² + 5x ⇒ 2x² – 5x – 3 – x² – 5x = 0 ⇒ x² – 10x – 3 = 0 is a Q.E. (or) Comparing the coefficients of x² on both sides. x . 2x and x . x ⇒ 2x² and x² 2x² ≠ x² Hence it’s a Q.E.

Check whether the following are quadratic equation.(x – 3) (2x + 1) = x(x + 5)

Answer»

Given: (x – 3) (2x + 1) = x(x + 5)

⇒ x (2x + 1) – 3 (2x + 1) = x . x + 5 . x

⇒ 2x² + x – 6x – 3 = x² + 5x

⇒ 2x² – 5x – 3 – x² – 5x = 0

⇒ x² – 10x – 3 = 0 is a Q.E.

(or)

Comparing the coefficients of x² on both sides.

x . 2x and x . x

⇒ 2x² and x²

2x² ≠ x²

Hence it’s a Q.E.