Question

.已知m,n为方程x2+2x-1=0的两个实数根，则m2-2n+2013=（）

.已知m,n为方程x²+2x-1=0的两个实数根，则m²-2n+2013=（）

Answer 1

m,n为方程x2+2x-1=0的两个实数根
∴m²+2m-1=0 即m²=1-2m
m+n=-2
m2-2n+2013
=1-2m-2n+2013
=1-2(m+n)+2013
=1-2×(-2)+2013
=2018

Answer 2

m+n=-2
m^2+2m-1=0
则m^2=-2m+1
m^2-2n+2013=-2m+1-2n+2013=-2(m+n)+2014=-2(-2)+2014=2018

Answer 3

m,n为方程x2+2x-1=0的两个实数根
得到m²+2m-1=0
m²=1-2m
m+n=-2
m²-2n+2013
=1-2m-2n+2013
=1-2(m+n)+2013
=1-2*(-2)+2013
=2018

望采纳
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