SOLUTION: 15x^2+10x-1=0 I was asked to find the discriminant. I said is 10x-1 and did it have 2 imaginary solutions, 2 real solutions or 1 real solution. I would say 1 real. am i right?

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: 15x^2+10x-1=0 I was asked to find the discriminant. I said is 10x-1 and did it have 2 imaginary solutions, 2 real solutions or 1 real solution. I would say 1 real. am i right?      Log On


   

Question 331974: 15x^2+10x-1=0 I was asked to find the discriminant. I said is 10x-1 and did it have 2 imaginary solutions, 2 real solutions or 1 real solution. I would say 1 real. am i right?
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
In a quadratic equation, the discriminant is that quantity that appears under the radical sign of the quadratic formula.
Here's the quadratic formula: x+=+%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a
The discriminant is: b%5E2-4ac and, for your problem, this would be:
10%5E2-4%2815%29%28-1%29 and when this is evaluated, it is:
100-%28-60%29+=+160
The discriminant is a positive quantity, the the quadratic equation will have two real roots.
Notice that the discriminant does not conain a variable, as you have shown in your answer!