已知m的2次方+m-1=0,求代数式m的3次方+5m的2次方+3m-2012的值

m^3+5m^2+3m-2012
=m^3+m^2+m^2+3m^2+3m-2012
=(m^3+m^2)+m^2+(3m^2+3m)-2012
=m(m^2+m)+m^2+3(m^2+m)-2012
因为m^2+m-1=0所以m^2+m=1
所以原式=m+m^2+3-2012=1+3-2012=-2008