SOLUTION: I'm lost. I've included the work I think is right. Solve the following quadratic equations. Make sure to show all your work. Use graphing to complete. 1. 3x2 + 11x � 20 = 0

Question 98239: I'm lost. I've included the work I think is right.
Solve the following quadratic equations. Make sure to show all your work. Use graphing to complete.
1. 3x2 + 11x � 20 = 0
� Graphing Method
� 3x2+11x-20=0
� 3x2+11x-20+20=0+20
� 3x2+11x=20
� X2+11/3=20/3
�

Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
Let's use the quadratic formula to solve for x:

Starting with the general quadratic

the general solution using the quadratic equation is:

So lets solve ( notice , , and )

Plug in a=3, b=11, and c=-20

Square 11 to get 121

Multiply to get

Combine like terms in the radicand (everything under the square root)

Simplify the square root (note: If you need help with simplifying the square root, check out this solver)

Multiply 2 and 3 to get 6

So now the expression breaks down into two parts

or

Lets look at the first part:

Add the terms in the numerator
Divide

So one answer is

Now lets look at the second part:

Subtract the terms in the numerator
Divide

So another answer is

So our solutions are:
or

Notice when we graph , we get:

and we can see that the roots are and . This verifies our answer
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