SOLUTION: when the sum of 8 and 18 times a positive number is subtracted from the square of the number, the result is 0. Find the number

Hi

n^2 - (8 + 18n) = 0

n^2 - 18n - 8 = 0

n(positive number) = 18.4339811320566 = 9 + √89

 


 
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation  (in our case ) has the following solutons:

  

  

  

  For these solutions to exist, the discriminant  should not be a negative number.

  

  First, we need to compute the discriminant : .

  

  Discriminant d=356 is greater than zero. That means that there are two solutions: .

  

    

    

    

    Quadratic expression  can be factored:

  

  Again, the answer is: 18.4339811320566, -0.433981132056603.
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