SOLUTION: Solve using the quadratic formula: 25x^2+30x+9=0 I do not understand this at all, please help :)

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve using the quadratic formula: 25x^2+30x+9=0 I do not understand this at all, please help :)      Log On


   

Question 172320This question is from textbook
: Solve using the quadratic formula: 25x^2+30x+9=0
I do not understand this at all, please help :) This question is from textbook

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Solve using the quadratic formula: 25x^2+30x+9=0
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Using the quadratic formula is just plugging in a, b and c.
For this one, a = 25, b = 30 and c = 9.
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 25x%5E2%2B30x%2B9+=+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=%2830%29%5E2-4%2A25%2A9=0.

Discriminant d=0 is zero! That means that there is only one solution: x+=+%28-%2830%29%29%2F2%5C25.
Expression can be factored: 25x%5E2%2B30x%2B9+=+%28x--0.6%29%2A%28x--0.6%29

Again, the answer is: -0.6, -0.6. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+25%2Ax%5E2%2B30%2Ax%2B9+%29

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The onsite solver gives more detail then you might need, but it gets the answers, shows how it's done, and shows a graph.