> find*a*polynomial*f;

 in F[7][x] ofdegree less than 4 solving the congruence(x^(2)-1)∗f≡x^(3)+2*x+5 mod x^(4)+2*x+1 inF[7][x] .;

show that the residue class ring F[343]=F[7][x]/is a field,and computer the inverse of x^(2) mod x^(3)+x+1in F[343].

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