Question

When 3 times a number is added to the square of the number, the result is 40. Determine the number

Answer 1

5 or -8

Explanation:

`(3 * x) + x {}^(2) = 40`

`3x + {x}^(2) = 40`

`{x}^(2) + 3x - 40 = 0`

using factorization method

`( {x}^(2) + 8x) ( - 5x - 40) = 0`

`x(x + 8) - 5(x + 8) = 0`

`(x - 5)(x + 8) = 0`

`x - 5 = 0`

or

`x + 8 = 0`

`x = 5`

or

`x = - 8`