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;
[tex]x^2 + 3x = 18\\x^2 + 3x - 18 =0[/tex]
Factorize the resulting equation:
[tex]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[/tex]
Hence the required numbers are 3 and -6
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