Question

x的平方+x-1=0,则x的三次方加2x平方减2014等于多少

Answer 1

因为：x^2 + x - 1 = 0
所以：x^2 + x = 1
所以,x^3 + 2x^2 - 2014 = x^3 + x^2 + x^2 - 2014
= x(x^2 + x) + x^2 - 2014
= x + x^2 - 2014
= 1 - 2014
= 2013