Example--Verification (s-1)2(s+2)(s+3)=s4+3s3-3s2-7s+6 1 -3 6 3 -7 0 -2 6 3 0 S 20 0 S 6 Examine 1st column,of sign changes= 日96Example--Verification ( s  1) 2 ( s  2)( s  3)  s 4  3 s 3  3 s 2  7 s  6 4 3 2 0 1 36 3 70 s s s s s   2 3  6 20 0 6 0 Examine 1st column, # of sign changes=