Question

已知m的平方加m减1等于0,求m的立方加2乘以m的平方减2013的值

Answer 1

因为m^2 + m - 1 = 0
所以 m^2 + m = 1
用m^2+m=1这个式子整体代值
代入下面的式子
m^3 + 2m^2 - 2013
= m(m^2+m+m) - 2013
= m(1+m) - 2013
= m^2 + m -2013
= 1 -2013
= -2012
用逐渐降次的方法解题。

Answer 2

因为m^2 + m - 1 = 0
所以 m^2 + m = 1代入下面的式子
用降次的方法解题

m^3 + 2m^2 - 2013
= m(m^2+m+m) - 2013
= m(1+m) - 2013
= m^2 + m -2013
= 1 -2013
= -2012
请采纳！！！

Answer 3

m^2 + m - 1 = 0 => m^2 + m = 1代入下面的式子

m^3 + 2*m^2 - 2013
= m*(m^2+m+m) - 2013
= m*(1+m) - 2013
= m^2 + m -2013
= 1 -2013
= -2012