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FInd the sum of the solutions of the quadratic x^2+7x-18

 Dec 28, 2022
 #1
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-1

Learn to use the "quadratic formula". That will give you 2 simple values for x.

 Dec 28, 2022
 #2
avatar+13 
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Using Vieta, the roots sum to -7.

 Dec 28, 2022
 #3
avatar+105 
+2

People, use the STEP BY STEP EXPLANATION... (although they prob only care about the answer)

 

The first thing we should do is understand how to factor. We need two numbers that multiply to -18, but add up to 7, let's look at all the factors of 18.

 

1,2,3,6,9,18

Inspecting further, we realize that 9 and 2 multiply to 18, but we need them to multiply to -18. So, we realize that our two numbers would be:

 

-2 and 9

 

Putting this into our little fancy factoring parentheses, we get:

 

(r-2)(x+9)

 

So the answers would pe r = 2 or s = -9

So, 2 + -9 = -7, so the sum is -7.

 Dec 29, 2022

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