Question 714846
<pre>
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 = {{{(-b +- sqrt( b^2-4*a*c ))/(2*a) }}}

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

x = {{{(-5 +- sqrt( 5^2-4*3*(-21) ))/(2*3) }}}

x = {{{(-5 +- sqrt(25+252 ))/6 }}}

x = {{{(-5 +- sqrt(277 ))/6 }}}

The two zeros are

{{{(-5 + sqrt(277 ))/6 }}} and x = {{{(-5 - sqrt(277 ))/6 }}}

Edwin</pre>