Question

La suma del cuadrado de un número más el triple del mismo número es igual a dieciocho. Encuentra dicho número.

Answer 1

If the sum of the square of a number plus the triple of the same number equals eighteen, the required numbers are 3 and -6

Let the unknown number be x

The square of the number is expressed as x²

Triple of the unknown number will also be expressed as 3x

Taking the sum of both numbers and equating it to 18 will give;

$x^2 + 3x = 18\\x^2 + 3x - 18 =0$

Factorize the resulting equation:

$x^2+3x -18=0\\x^2+6x-3x-18=0\\x(x+6)-3(x+6)=0\\(x-3)(x+6)=0\\x= 3 \ and \ -6$

Hence the required numbers are 3 and -6

Learn more here; brainly.com/question/13805464