2a²-3ab=23,两边乘4 4ab+b²=9两边乘3 然后两式相加得8a²+3b²=119
(a+2)²+|b+5|=0,a=-2 b=-5
求3a²b-[2a²b-(2ab-a²b)-4a²]-ab
=3a²b-[2a²b-2ab+a²b-4a²]-ab
=3a²b-2a²b+2ab-a²b+4a²-ab
=4a²+ab
=16+10
=26
|a|-|a+b|+|c-a|+|b-c|.
=-a-a-b+c-a+c-b
=-3a-2b+2c
2a²-3ab=23,两边乘4 4ab+b²=9两边乘3 然后两式相加得8a²+3b²=119
(a+2)²+|b+5|=0,a=-2 b=-5
求3a²b-[2a²b-(2ab-a²b)-4a²]-ab
=3a²b-[2a²b-2ab+a²b-4a²]-ab
=3a²b-2a²b+2ab-a²b+4a²-ab
=4a²+ab
=16+10
=26
|a|-|a+b|+|c-a|+|b-c|.
=-a-a-b+c-a+c-b
=-3a-2b+2c