整式乘除与因式分解的初一题
1.化简
(1)(2a+1)(-a-2)+a(2-a)
(2)[(x+y)²-(x+y)(x-y)]÷(-2-y)
2.分解因式
-2x³+8xy²
3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
人气:245 ℃ 时间:2020-05-21 23:05:15
解答
1. 化简 (1) (2a+1)(-a-2)+a(2-a) = (-2a² -5a -2) +(2a -a²) =-3a²-3a-2 (2) [(x+y)²-(x+y)(x-y)]÷(-2-y) = [(x² +2xy +y²) -(x² -y²)] ÷ [-(y+2)] = -[2y² +2xy...
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