SOLUTION: Okay so I understand how to factor this question 3x^2-15x-60, but do I have to factor this equation out before I use the quadratic formula? if so this is what I have 3(x^2-5x-20)

Question 227626: Okay so I understand how to factor this question 3x^2-15x-60, but do I have to factor this equation out before I use the quadratic formula? if so this is what I have 3(x^2-5x-20) my question is can you show me how to plug it into the quadratic formula?
Thanks.
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Okay so I understand how to factor this question 3x^2-15x-60, but do I have to factor this equation out before I use the quadratic formula? if so this is what I have 3(x^2-5x-20) my question is can you show me how to plug it into the quadratic formula?
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First, 3x^2-15x-60 is not an equation. There's no equal sign, so it's not an equation.
You mention solving it using the quadratic equation, so maybe it's = 0??
3x^2-15x-60 = 0 is and equation, and can be solved.
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You can can factor out the 3, then use the quadratic equation. The results will be the same whether you do that or not. Factoring it gives you smaller number to work with in the quadratic formula.
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Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=105 is greater than zero. That means that there are two solutions: .

Quadratic expression can be factored:

Again, the answer is: 7.6234753829798, -2.6234753829798. Here's your graph:

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