摘要：已知A＝x3-2x2+x-7.B＝6x2-8x+4.C＝x3-2x2-9. 求:4A-2B+3C. 思路解析:本题考查整式的运算.注意加括号. 解:(1)A-2B+C＝(x3-2x2+x-7)-2(6x2-8x+4)+(x3-2x2-9)= 2x3-16x2+17x-24, (2)4A-2B+3C＝4(x3-2x2+x-7)-2(6x2-8x+4)+3(x3-2x2-9)=7x3-26x2+20x-63.

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