Question

The sum of the square of a number with the number itself is 12. Calculate this number.

Answer 1

This number can be 3 or - 4.

Explanation :

we will call This number of x. > Therefore, the expression "The sum of the square of x with X itself is 12" , is:

x² + x = 12

x² + x - 12 = 0

We have a 2nd degree equation.

Your coefficients are: A = 1, B = 1, C = -12.

Using Bháskara formula :

Δ = b² - 4ac

Δ = 1² - 4.1. = 49

x = - B ± √δ

2a

x = - 1 ± √49

2.1

x = - 1 ± 7

2

x ' = - 1 + 7 = 6 = 3

2

x '' = - 1- 7 = - 8 = - 4

2 2

Therefore, this number can be 3 or - 4.

Answer 2

Explanation:

Let the number be x

we get this equation,

`x^2 + x - 12 = 0\\(x+4)(x-3) = 0`

from this we conclude x to be -4 or 3