1.m^2+13m+1=0,m^3+12m^2-12m+2004=?2.已知x=a^2+2a+b^2,y=4b-7,比较x、y的大小
问题描述:
1.m^2+13m+1=0,m^3+12m^2-12m+2004=?2.已知x=a^2+2a+b^2,y=4b-7,比较x、y的大小
答
m^3+12m^2-12m+2004=m³+13m²+m-m²-13m+2004=m(m²+13m+1)-(m²+13m+1)+2005=0-0+2005=2005x-y=a²+2a+b²-4b+7=(a+1)²+(b-2)²+2>0∴x>y