如果A等于a的平方+a+1,B=a的平方-a-1,化简:A-【B-A-(A-2B)】:

问题描述:

如果A等于a的平方+a+1,B=a的平方-a-1,化简:A-【B-A-(A-2B)】:

将A、B的式子代入代数式A-[B-A-(A-2B)]=A-[B-A-A+2B]=A-[3B-2A]=A-3B+2A=3A-3B=3(A-B)=3[a^2+a+1-(a^2-a-1)]=3[a^2+a+1-a^2+a+1]=3(2a+2)=6a+6

A-【B-A-(A-2B)】
=A-(B-A-A+2B)
=A-(3B-2A)
=A-3B+2A
=3A-3B
=3(a²+a+1)-3(a²-a-1)
=3a²+3a+3-3a²+3a+3
=6a+3