(1)(X³-2x²+x-4)-(2x³-5x-4) (2)3(a²-2a-3)-5(-5a²+a-2)

问题描述:

(1)(X³-2x²+x-4)-(2x³-5x-4) (2)3(a²-2a-3)-5(-5a²+a-2)

(X³-2x²+x-4)-(2x³-5x-4) =x³-2x²+x-4-2x³+5x+4=x³-2x³-2x²-4+4=-x³-2x²3(a²-2a-3)-5(-5a²+a-2)=3a²-6a-9+25a²-5a+10=3a²+25a...