Question

已知a=2b+3a，则2ab+b等于多少？

Answer 1

2a＝一2b，a＝一b，2ab＋b＝b一2b＾2，无法计算出准确值

Answer 2

(a-b)³

=(a-b)²(a-b)

=(a²-2ab+b²)(a-b)

=a(a²-2ab+b²)-b(a²-2ab+b²)

=a³-2a²b+ab²-a²b+2ab²-b³

=a³-3a²b+3ab²-b³

拓展资料：

1、(a+b)³

=(a+b)²(a+b)

=(a²+2ab+b²)(a+b)

=a(a²+2ab+b²)+b(a²+2ab+b²)

=a³+2a²b+ab²+a²b+2ab²+b³

=a³+3a²b+3ab²+b³

2、(a+b)^4

=(a+b)³(a+b)

=(a³+3a²b+3ab²+b³)(a+b)

=a(a³+3a²b+3ab²+b³)+b(a³+3a²b+3ab²+b³)

=a^4+4a³b+6a²b²+4ab³+b^4

3、（a-b)^4

=(a-b)³(a-b)

=(a³-3a²b+3ab²-b³)(a-b)

=a(a³-3a²b+3ab²-b³)-b(a³-3a²b+3ab²-b³)

=a^4-4a³b+6a²b²-4ab³+b^4