已知x2+x-1=0求x3+2x2+1988的值.

来源：学生作业帮助网编辑：作业帮时间：2024/07/14 13:47:27

x��PM �@��2��q�ҌG �!�yˈ��-jӪAO�K��8Ϧ?73��q��.�񄜡��8/�g\Q� ?��E��ת΋#�~"v;0�\��\MehI��t�q�� K w9~��WT(�<O��B��DG�J�� π@S'�|�Y\�X�"Rbz�bW�1��W�U��c��˅�۴�¢L�t�%{#Ix�U��Ke��"M�[�� s~��

已知x2+x-1=0求x3+2x2+1988的值.
已知x2+x-1=0求x3+2x2+1988的值.

已知x2+x-1=0求x3+2x2+1988的值.
x²=1-x
∴x3+2x2+1998
=(1-x)x+2(1-x)+1988
=x-(1-x)+2-2x+1988
=x-1+x+2-2x+1988
=1989

=x(x^2+x-1)+(x^2+x)+1988=0+1+1988=1989

x^3 + 2x^2 = x^3 + x^2 + x^2 = x(x^2 + x) + x^2 = x^2 + x = 1
故x^3 + 2x^2 + 1988 = 1989

x²+x-1=0，则x²+x=1
x³+2x²+1988
=x³+x²+x²+1988
=x（x²+x）+x²+1988
=x+x²+1988
=1+1988
=1989

已知x2+5x-4=0,求x3+6x2+x+2的值已知x2+x-1=0,求x3+2x2+3的值已知X3+X2+X+1=0,求1+X+X2+X3+X4的值已知x2+x+1=0,求x4+2x3-x2-2x+2014 已知x2-3x+1=0,求x4-6x3+4x2+15x+2 已知x2+x-1=0求x3+2x2+1988的值. 已知：X2次方;-X-1=0 求：-X3次方;+2X2次方;+2003的值? 已知x2-x-1=0,求-x3+2x2+2007如题已知x2+x-1=0,求x3+2x2+3的值已知x2+x-1=0,求x3+2x2+2005 若 x2-3x+1=0,求（2x2×x3-5x2×x2+2 x3-8x2 ）÷（x2+1 ）的值已知x2+3x2+1=0,求x3+x3分之一+2的值已知x4+x3+x2+x+1=0,求1+x+x2+...+x2010的值已知x4+x3+x2+x+1=0,求 1+x+x2+...+x2009的值已知x4+x3+x2+x+1=0,求1+x+x2+...+x2010的值已知x2-3x-1=0求x3-3x2-11x+8的值已知x2+x+!=0求1+x+x2+x3+x4.+x2006的值已知X2-X-1=0求,X5-X4-3X3+3X2+X的值已知1+x+x2+x3=0,求x+x2+x3+….x2011+2012的值.已知1+x+x2+x3=0,求x+x2+x3+….x2011+2012的值.