SOLUTION: 1. How many solutions exist for a quadratic equation? Explain and example 2. How do we determine whether the solutions are real or complex? Example.

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Question 330626: 1. How many solutions exist for a quadratic equation? Explain and example
2. How do we determine whether the solutions are real or complex? Example.

Answer by Fombitz(13828) About Me  (Show Source):
You can put this solution on YOUR website!
1.There are always two solutions to a quadratic equation.
They may be a complex conjugate pair solution or a real solution, which includes the possibility of a double root at one x value.
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2. Graphically, you can graph the function and see if it ever crosses the x axis. If it does, then the roots are real, if not, then the roots are complex.
Algebraically, use the discriminant,
D=b%5E2-4ac where the quadratic equation is in the form ax%5E2%2Bbx%2Bc=0.
If D%3E0, two real distinct roots.
If D=0, one real double root.
If D%3C0, two complex conjugate pair roots.
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graph%28300%2C300%2C-10%2C10%2C-10%2C10%2Cx%5E2%2B3x-10%2C%28x-5%29%5E2%2Cx%5E2%2Bx%2B2%29
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The red curve has two real roots, y=x%5E2%2B3x-10, D=9%2B40=49
The green curve has one real double root, y=x%5E2-10x%2B25,D=100-100=0
The blue curve has complex conjugate roots, y=x%5E2%2Bx%2B2,D=1-8=-7