Question

一道数学题！谢谢了

Answer 1

（3a²b-2ab）-(ab-4a²)+(3ab-a²b)

=3a²b-2ab- ab+4a²+3ab-a²b

=2a²b+4a²

无论a=2或-2，a²=4

所以原式=2×4×（-3）+4×4

        =-24+16

        =-8

Answer 2

先把括号打开化简 2a^2b-4a^2.所以±a的结果都相同