SOLUTION: What are the zeroes of 3x^2+5x-21

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Question 714846: What are the zeroes of 3x^2+5x-21
Found 2 solutions by lynnlo, Edwin McCravy:
Answer by lynnlo(4176) About Me  (Show Source):
You can put this solution on YOUR website!
±1,±1/3,±3,±7,±7/3,±21

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
The other tutor thought you were to list all the candidates for
possible rational zeros, not find the actual zeroes.  Let's find 
the zeros, not just list the candidates for zeroes.

3x² + 5x - 21

Set that = 0

3x² + 5x - 21 = 0

It doesn't factor, so we will have to use the quadratic formula:

x = %28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

where a = 3, b = 5, and c = -21 

x = %28-5+%2B-+sqrt%28+5%5E2-4%2A3%2A%28-21%29+%29%29%2F%282%2A3%29+

x = %28-5+%2B-+sqrt%2825%2B252+%29%29%2F6+

x = %28-5+%2B-+sqrt%28277+%29%29%2F6+

The two zeros are

%28-5+%2B+sqrt%28277+%29%29%2F6+ and x = %28-5+-+sqrt%28277+%29%29%2F6+

Edwin