来自李耀辉的问题
若x=17-1,则x5+2x4-17x3-x2+18x-16的值是______.
若x=
17-1,则x5+2x4-17x3-x2+18x-16的值是______.
1回答
2020-11-17 18:22
若x=17-1,则x5+2x4-17x3-x2+18x-16的值是______.
若x=
17-1,则x5+2x4-17x3-x2+18x-16的值是______.
∵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.