已知A=3a2次方-2a+1,B=5a2次方-3a+2,C=2A二次方-4a-2求A-B-C,

∵A=3a²-2a+1,B=5a²-3a+2,C=2a²-4a-2
∴A-B-C
=(3a²-2a+1)-(5a²-3a+2)-(2a²-4a-2)
=3a²-2a+1-5a²+3a-2-2a²+4a+2
=(3-5-2)a²+(-2+3+4)a+1
=-4a²+5a+1