解未知数1.已知x+y=4,求x^2+xy+4y的值2.已知m^2+2m+1=0,求m^3+2m^2+3m

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解未知数1.已知x+y=4,求x^2+xy+4y的值2.已知m^2+2m+1=0,求m^3+2m^2+3m
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解未知数1.已知x+y=4,求x^2+xy+4y的值2.已知m^2+2m+1=0,求m^3+2m^2+3m
解未知数
1.已知x+y=4,求x^2+xy+4y的值
2.已知m^2+2m+1=0,求m^3+2m^2+3m

解未知数1.已知x+y=4,求x^2+xy+4y的值2.已知m^2+2m+1=0,求m^3+2m^2+3m
1、
x+y=4
x^2+xy+4y
=x(x+y)+4y
=4x+4y
=4(x+y)
=16
2、
m^2+2m+1=0
(m+1)^2=0
m+1=0
m=-1
所以m^3+2m^2+3m
=-1+2-3
=-2