How do you find the discriminant of #5n ^ { 2} + 5n = - 9#?

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Answer 1 · 2017-06-02T03:58:21

The discriminant is #-155#.

#5n^2+5n=-9#

Move all terms to the left.

#5n^2+5n+9=0#

The quadratic equation is now in standard form: #ax^2+bx+c#, where #a=5#, #b=5#, and #c=9#.

The discriminant is #b^2-4ac#, which is under the square root symbol in the quadratic formula.

Now just insert the values and solve.

#"discriminant"=5^2-4*5*9#

Simplify.

#"discriminant"=25-180#

#"discriminant"=-155#