谢谢,第五题有答案吗
追答2. (4x²y-5xy²)-(3x²y-4xy²)
=4x²y-5xy²-3x²y+4xy²
= x²y- xy²
=xy(x-y)
4. 15+3(1-a)-(1-a-a²)+(1-a+a²-a³)
=15+3-3a-1+a+a2+1-a+a2-a3
=18-3a+2a2-a3
5,先化简,再求值
5x²+4-3x²-5X-2x²-5+6X
=5x²-3x²-2x²+6X-5X+4-5
=X-1
=-3-1
=-4
8.8. 3x²-(5x-(1/2x-3)+2x²)
=3 x²-5x+(1/2x-3)-2x²
=3 x²-5x+1/2x-3-2x²
= x²-9/2x-3
那好麻烦的