Let a,b,c,d be the four roots of the polynomial
x4+3x3−x2+x−2.
Given that a1+b1+c1+d1=21 and a21+b21+c21+d21=−43, the value of
a31+b31+c31+d31
can be expressed as nm for relatively prime positive integers m and n. Compute m+n.Proposed by Nathan Xiong