Five times of a positive integer is equal to 3 less than

Home » Aptitude » Number System » Question

Five times of a positive integer is equal to 3 less than twice the square of that number. The number is

Let the positive integer be x.
∴ 2x² – 5x = 3
⇒ 2x² – 3 = 0
⇒ 2x² – 6x + x – 3 = 0
⇒ 2x (x – 3) + 1 (x – 3) = 0
⇒ (x – 3) (2x + 1) = 0

∴ x = 3 and x = –	1
	2

is not admissible.