合并下类同类项,-3a+5a-6a[2]-3ax的二次方+2ax的二次方-4ax的二次方[3]3a-4b+5a-2b

-3a+5a-6a=(-3+5-6)a=-4a
-3ax²+2ax²-4ax²=(-3+2-4)ax²=-5ax²
3a-4b+5a-2b=(3+5)a-(4+2)b=8a-6b
2a²+1-3a+7-3a²+5a=-a²+2a+8
7ab-a²+2a²-5ab-3a²-4=-2a²+2ab-4