SOLUTION: please help with this. For the equation 3x^2-4x-5=0 find a,b,and c. a= b= c= Then solve the equation using the quadratic formula

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equation Customizable Word Problems -> SOLUTION: please help with this. For the equation 3x^2-4x-5=0 find a,b,and c. a= b= c= Then solve the equation using the quadratic formula      Log On


   

Question 432246: please help with this.
For the equation 3x^2-4x-5=0
find a,b,and c.
a=
b=
c=
Then solve the equation using the quadratic formula
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
For the equation 3x^2-4x-5=0
find a,b,and c.
-----------
a = 3
b = -4
c = -5
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 3x%5E2%2B-4x%2B-5+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-4%29%5E2-4%2A3%2A-5=76.

Discriminant d=76 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--4%2B-sqrt%28+76+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-4%29%2Bsqrt%28+76+%29%29%2F2%5C3+=+2.11963298118022
x%5B2%5D+=+%28-%28-4%29-sqrt%28+76+%29%29%2F2%5C3+=+-0.786299647846891

Quadratic expression 3x%5E2%2B-4x%2B-5 can be factored:
3x%5E2%2B-4x%2B-5+=+%28x-2.11963298118022%29%2A%28x--0.786299647846891%29
Again, the answer is: 2.11963298118022, -0.786299647846891. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+3%2Ax%5E2%2B-4%2Ax%2B-5+%29