Question

Five times of a positive whole number is 3 less than twice the square of the number. The number is
​

Answer 1

Answer:

4.5/5

73

abhi569

Genius

6.6K answers

5.2M people helped

Let the number be x,

5 times of x = 5x

3 less than twice of square of x = 2x² - 3

In question,

→ 5x = 2x²- 3

→ 2x² - 5x - 3 = 0

→ 2x² - (6 - 1)x -3 = 0

→ 2x² - 6x + x - 3 = 0

→ 2x(x -3) +1(x-3) = 0

→ (x -3) (2x +1) = 0

x = 3 or x = (-1/2)

x can't be negative (Given in the Question), so number is 3

Answer 2

Answer:

Let a number = x

5 times of x = 5x

3 less than twice of square of x = 2(x*x ) - 3

Explanation:

5x = 2(x*x) - 3

2(x*x) - 5x - 3 = 0

2(x*x) - (6-1)x - 3 = 0

2x(x-3) + 1(x-3) = 0

(x-3) (2x+1) = 0

x =3 or x=(-1/2)

x can't be a negative number.

so,

x =3