text: solve this problem please? please show work  s^3+4s^2-s-4=0   thanks a lot factor by grouping (s^3 + 4s^2) + (-s - 4) = 0 s^2 (s+4) + (-1)(s+4) = 0 (s+4)(s^2 -1) = 0 (s+4)(s+1)(s-1) = 0 s+4 = 0 or s+1 = 0 or s-1 = 0 s = -4, -1 or 1