Question

1.已知m的平方+m-1=0,则m的三次方+2m的平方+2004=（）

Answer 1

1

m^2+m-1=0

m^2+m=1

m^3+2m^2+2004

=m(m^2+m)+m^2+2004

=m+m^2+2004

=1+2004=2005

(1/2)(a^2+b^2)-ab

=(1/2)(a^2+b^2-2ab)

=(1/2)(a-b)^2

=(1/2)×1

=1/2

(x+2)^2-(y+2)^2=4

(x+2+y+2)(x+2-y-2)=4

(x+y+4)(x-y)=4

4(x-y)=4

4×2x=4

2x=1

x=1/2

y=-1/2