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+8xy²3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
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![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+8xy²3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值](/uploads/image/z/1239670-46-0.jpg?t=%E6%95%B4%E5%BC%8F%E4%B9%98%E9%99%A4%E4%B8%8E%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3%E7%9A%84%E5%88%9D%E4%B8%80%E9%A2%981.%E5%8C%96%E7%AE%80%EF%BC%881%EF%BC%89%282a%2B1%29%28-a-2%29%2Ba%282-a%29%282%29%5B%28x%2By%29%26sup2%3B-%28x%2By%29%28x-y%29%5D%C3%B7%28-2-y%292.%E5%88%86%E8%A7%A3%E5%9B%A0%E5%BC%8F-2x%26sup3%3B%2B8xy%26sup2%3B3.%E5%B7%B2%E7%9F%A5x%26sup2%3B-2x%3D2%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8F%EF%BC%88x-1%EF%BC%89%26sup2%3B%2B%EF%BC%88x%2B3%EF%BC%89%EF%BC%88x-3%EF%BC%89%2B%EF%BC%88x-3%EF%BC%89%EF%BC%88x-1%EF%BC%89%E7%9A%84%E5%80%BC)
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+8xy²3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
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
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+8xy²3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
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] ÷ (y+2)
= -(2y² +2xy)/(y+2)
=2xy/-y-2
2. 分解因式
-2x³+8xy²
= -2x(x² -4y²)
= -2x(x+2y)(x-2y)
3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
(x-1)²+(x+3)(x-3)+(x-3)(x-1)
= (x² -2x +1) +(x² -9) +(x² -4x +3)
= 3x² -6x -5
= 3(x² -2) -5
当x²-2x=2时
原式
= 3*2 -5
= 1.
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)] ÷ [...
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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] ÷ (y+2)
= -(2y² +2xy)/(y+2)
2. 分解因式
-2x³+8xy²
= -2x(x² -4y²)
= -2x(x+2y)(x-2y)
3.已知x²-2x=2,求代数式(x-1)²+(x+3)(x-3)+(x-3)(x-1)的值
(x-1)²+(x+3)(x-3)+(x-3)(x-1)
= (x² -2x +1) +(x² -9) +(x² -4x +3)
= 3x² -6x -5
= 3(x² -2) -5 (将x²-2x=2带入)
= 3*2 -5
= 1.
收起
1.(1)原式=-2a2-4a-a-2+2a-a2=-3a2-3a-2
(2)原式=(x2+y2+2xy-x2+y2)/-2-y=2y2+2xy/-2-y
2.原式=-2x(x2-4y2)=-2x(x+2y)(x-2y)
3.原式=x2+1-2x+x2-9+x2-4x+3=3x2-6x-5
=3(x2-2x)-5=6-5=1
(字母前的数字表示系数,字母后的数字表示幂)
1.(1)
-3a²-3a-2
(2)
2xy
----
-y-2
2.-2x(x²-4y²)
3.
化简:3(x²-2x)-5
原式=1