Question

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

Answer 1

x = the number 

5x = 2x² - 3 {five times the number equals three less than twice the square} 
2x² - 5x - 3 = 0 {subtracted 5x from both sides} 
(2x + 1)(x - 3) = 0 {factored into two binomials} 
2x + 1 = 0 or x - 3 = 0 {set each factor equal to 0} 
2x = -1 or x = 3 {subtracted 1 and added 3 respectively} 
x = -1/2 or x = 3 {divided left equation by 2} 

x = 3