1.已知a+2b=0,则式子a3+2ab(a+b)+4b3=a2(a+2b)+2b2(a+2b)=0
2.如果1+x+x2+x3=0,求x+x2+x3+x4+x5+x6+x7+x8
=x(1+x+x2+x3)+x5(1+x+x2+x3)=0
3.若x2-4x+b=(x-2)×(x+a),
x2-4x+b=x2+(a-2)x-2a
则a=-2,b=4
1.已知a+2b=0,则式子a3+2ab(a+b)+4b3=a2(a+2b)+2b2(a+2b)=0
2.如果1+x+x2+x3=0,求x+x2+x3+x4+x5+x6+x7+x8
=x(1+x+x2+x3)+x5(1+x+x2+x3)=0
3.若x2-4x+b=(x-2)×(x+a),
x2-4x+b=x2+(a-2)x-2a
则a=-2,b=4