SOLUTION: what is the sum of the roots of this equation. ax^2+bx+c=0 im not sure what they mean by this.

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Question 280070: what is the sum of the roots of this equation. ax^2+bx+c=0 im not sure what they mean by this.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The roots are the values of x that make
the equation true.
ax%5E2+%2B+bx+%2B+c+=+0
The quadratic formula for the roots is:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
So, the 2 roots are:
x%5B1%5D+=+%28-b+%2B+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x%5B2%5D+=+%28-b+-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x%5B1%5D+%2B+x%5B2%5D+=+-b%2F%282a%29+-+b%2F%282a%29+
x%5B1%5D+%2B+x%5B2%5D+=+-b%2Fa
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Another way to do it is:
ax%5E2+%2B+bx+%2B+c+=+0
x%5E2+%2B+%28b%2Fa%29%2Ax+%2B+c%2Fa+=+0
Call the roots r%5B1%5D and r%5B2%5D, then
%28x+-+r%5B1%5D%29%2A%28x+-+r%5B2%5D%29+=+0
x%5E2+-+%28r%5B1%5D+%2B+r%5B2%5D%29%2Ax+%2B+r%5B1%5D%2Ar%5B2%5D+=+0
-%28r%5B1%5D+%2B+r%5B2%5D%29+=+b%2Fa
r%5B1%5D+%2B+r%5B2%5D+=+-b%2Fa