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

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

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