∵x=17-1，∴（x+1）2=17，化简得到：x2+2x=16，∴x5+2x4-17x3-x2+18x-16=x3（x2+2x）-17x3-x2+18x-16=16x3-17x3-x2+18x-16=-x3-x2+18x-16=-x（x2+2x）+x2+18x-16=x2+2x-16=16-16=0．