1.已知m的2次方+m-1=0求代数式m的3次方+2m的2次方+2006的值

m²+m-1=0
m²+m=1
m³+2m²+2006
=(m³+m²)+m²+2006
=m(m²+m)+m²+2006
=m+m²+2006
=1+2006
=2007
a²+b²-4a+6b+18
=a²+b²-4a+6b+4+9+5
=(a²-4a+4)+(b²+6b+9)+5
=(a-2)²+(b+3)²+5
最小值是5,此时a=2,b=-3