SOLUTION: Compute the value of the discriminant and give the number of real solutions to the quadratic equation. 2x^2-8x-1=0

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Compute the value of the discriminant and give the number of real solutions to the quadratic equation. 2x^2-8x-1=0      Log On


   

Question 347971: Compute the value of the discriminant and give the number of real solutions to the quadratic equation.
2x^2-8x-1=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
From 2x%5E2-8x-1 we can see that a=2, b=-8, and c=-1


D=b%5E2-4ac Start with the discriminant formula.


D=%28-8%29%5E2-4%282%29%28-1%29 Plug in a=2, b=-8, and c=-1


D=64-4%282%29%28-1%29 Square -8 to get 64


D=64--8 Multiply 4%282%29%28-1%29 to get %288%29%28-1%29=-8


D=64%2B8 Rewrite D=64--8 as D=64%2B8


D=72 Add 64 to 8 to get 72


So the discriminant is D=72


Since the discriminant is greater than zero, this means that there are two real solutions.


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Jim