Using a graphic tool.
<span>see attached graphic</span>
<span>
the solutions are
x1=-2
x2=0.811
</span>check
<span>see attached graphic</span>
<span>
the solutions are
x1=-2
x2=0.811
</span>check
for x=-2
x^4+3x^3+3x2-3x-4
(-2) ^4+3(-2) ^3+3(-2) ^2-4=16+(-24)+12-4=0 ok
For x=0.811
(0.811) ^4+3(0.811) ^3+3(0.811) ^2-4=0.4326+(1.6002)+1.9731-4=0 ok