How do you use the discriminant to determine the nature of the solutions given # n^2 – 18n + 81 = 0#?

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Answer 1 · 2017-01-19T07:02:34

The answer is #S={9}#

We compare this equation to

#ax^2+bx+c=0#

#n^2-18n+81=0#

The discriminant is #Delta=b^2-4ac#

#Delta=(-18)^2-4*1*81=324-324=0#

As #Delta=0#, there is a double real root

#n=-b/(2a)=18/2=9#