问题
填空题
已知x2+x-1 = 0,则代数式x3+2x2+2011的值为 .
答案
2012
∵x2+x-1=0,∴x2+x=1,
x3+2x2+2011,
=x(x2+x)+x2+2011,
=x+x2+2011,
=2012,
已知x2+x-1 = 0,则代数式x3+2x2+2011的值为 .
2012
∵x2+x-1=0,∴x2+x=1,
x3+2x2+2011,
=x(x2+x)+x2+2011,
=x+x2+2011,
=2012,