Question 953927
{{{graph(300,300,-5,5,-5,5,x^4+2x^3-2x^2-3x+2)}}}
By the rational roots theorem, the possible rational roots are +/-1 and +/-2.
Looks like {{{x=-2}}} and {{{x=1}}} are zeros.
Plug them in to verify.
I'll do one, you do the other,
{{{1^4+2(1)^3-2(1)^2-3(1)+2=1+2-2-3+2=0}}}
By the graph and the rational roots theorem, the other two roots are not rational.