数学题☞2a²-3ab+4b²-5ab-6b²☞3a²-5a+2-6a²-3,其中a=-1

数学题☞2a²-3ab+4b²-5ab-6b²☞3a²-5a+2-6a²-3,其中a=-1
数学题☞2a²-3ab+4b²-5ab-6b²☞3a²-5a+2-6a²-3,其中a=-1

数学题☞2a²-3ab+4b²-5ab-6b²☞3a²-5a+2-6a²-3,其中a=-1
1.2a²-3ab+4b²-5ab-6b²
=2a²-8ab-2b²
第一题应该不用求值吧0 0
2.3a²-5a+2-6a²-3
=-3a²-11a-1
其中a=-1
则 -3a²-11a-1
=（-3）×（-1)²-11×（-1）-1
=-3+11-1
=7

你要求什么.....?
求b吗...

∵a=-1
∴3a²-5a+2-6a²-3=3×（﹣1）²-5×（-1）＋2-6×（-1）²-3=3-（-5）＋2-6=4

好……好复杂的题啊