若x²+x-1=0,求X^3+2x²+2的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/14 07:50:16
![若x²+x-1=0,求X^3+2x²+2的值](/uploads/image/z/7164394-34-4.jpg?t=%E8%8B%A5x%26%23178%3B%2Bx-1%3D0%2C%E6%B1%82X%5E3%2B2x%26%23178%3B%2B2%E7%9A%84%E5%80%BC)
x){ѽBMZB@Ʀ8cm#Y-O$XΆD|X̩3Ү5|ۊ'?m]
4kOӵ F`¶BB~qAb56`
mP#@nzcɋ};Ny6}ۓ3^6i{fZBFeu6TBdm#tr(K( BQYm,O`+v/|lwmO,۾Lg*V "" (
жB,mcrmN! j1
若x²+x-1=0,求X^3+2x²+2的值
若x²+x-1=0,求X^3+2x²+2的值
若x²+x-1=0,求X^3+2x²+2的值
等于3,
x^2+x=1
x^3+x^2=x代入求的式子
x-x^2+2x^2+2=x+x^2+2=1+2=3
将X²+X-1=0两边同时乘以X
则:X³+X²-X=0
所以X³=X-X²
所以X^3+2x²+2
=X-X²+2X²+2
=X+X²+2
=1+2
=3
满意望采纳
X^3+2x²+2
=(x^3+x²-x)+ (x²+x-1) +1+2
=x*(x²+x-1) + (x²+x-1)+3
=x*0+0+3
=3
=3