Question 22998
Do you mean:
{{{x^4 -9x^2 - 112 = 0}}}


You need to factor this by finding two numbers whose product is 112 and whose difference is 9.  If you can't think of the combination, start at the beginning with 1:


1*112
2* 56
3 does not go into 112
4* 28
7* 16  


That's it!  There is the difference of 9!

{{{x^4 - 9x^2 -112 = 0}}}
{{{ (x^2 - 16)(x^2+7)= 0}}}
{{{x^2-16 = 0 }}}  or    {{{x^2+7 = 0}}}
{{{x^2=16}}}  or {{{x^2= -7}}}
{{{x= 4}}} {{{x=-4}}} 
There are no real numbers that you can square to get a negative number, so {{{x^2=-7}}} has no real solutions.  If you wanted complex solutions also, then the solutions of the last part would be {{{x= 0+-i *sqrt(7) }}}


R^2 at SCC