Question 983280
Factorize?  Best try synthetic division, as if for checking possible roots.  If remainder of 0, then value checked is a root of the equation.  When one root found, the two other roots will come from handling the result quadratic expression  (the quotient from the first root found).


<pre>

-1    |    1     -7    -6    3
      |
      |          -1     6    0
      |______________________________
           1     -6     0     3



+1    |    1     -7    -6    3
      |
      |           1    -6   -12
      |______________________________
           1      -6    -12   -9



-3    |    1     -7    -6    3
      |
      |          -3    30    -72
      |______________________________
           1     -10   24    -69


+3    |    1     -7    -6    3
      |
      |          3     -12   -54
      |______________________________
           1     -4    -18   -51


</pre>


All the possible RATIONAL roots failed to give remainder of 0.


Next method should be some numerical root finding approximation.  You might also use a graphing tool. 


If you are in a hurry  (no longer likely), or want to recheck your results, or you believe some roots are complex or irrational, you might try using this:
http://xrjunque.nom.es/rootfinder.aspx