1) 3 х^3-7 х^2-7 х+3=0

2) х^4+5 х^3+6 х^2+5 х+1=0

1) 3 х^3-7 х^2-7 х+3=0

(3 х^3+3) - (7 х^2+7 х) = 0

3 (х^3+1) - 7 х (х+1) = 0

3 (х+1) (х^2-х+1) - 7 х (х+1) = 0

(х+1) (3 (х^2-х+1) - 7 х) = 0

(х+1) (3 х^2-3 х+3-7 х) = 0

(х+1) (3 х^2-10 х+3) = 0

а) х+1=0

х1 = - 1

б) 3 х^2-10 х+3=0

D=b^2-4ac

D=100-4*3*3=100-36=64

x2 = (10+8) / 6=18/6=3

x3 = (10-8) / 6=2/6=1/3

Ответ: х1=1; х2=3; х3=1/3