问几题初三数学因式分解的题目。
1、8a^3-b^3=(2a)^3-b^3=(2a-b)(4a^2+2ab+b^2)2、原式＝4x-4y+4+y^2-2xy
=(4x-2xy)+(y^2-4y+4)
=2x(2-y)+(y-2)^2
=(y-2)(y-2-2x)
3、原式=(3x-y)(x+2y)+x+9y-4
=(3x-y)(x+2y)-(3x-y)+4x+8y-4
=(3x-y)(x+2y-1)+4(x+2y-1)
=(3x-y+4)(x+2y-1)
4、3x²+4xy-y²
=4x²+4xy-y²
-x²
=(2x-y)²
--x²
=(3x-y)(x+y)
5、x²+x-(a²-a)
=(x²-a²)+x+a
=(x+a)(x-a)+(x+a)
=(x+a)(x-a+1)
将式子分配一下就可以了
6、a^3+1=(a+1)(a^2-a+1)
a^3-1=(a-1)(a^2+a-1)
这是公式，要记住！
化学：用n=m/M算
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绛旓細浜屻佸～鍏呴 1.鑻2x3+3x2+mx+1涓簒+1鐨勫嶅紡,鍒檓= 2.鍥犲紡鍒嗚В3a3b2c-6a2b2c2+9ab2c3= 3.鍥犲紡鍒嗚Вxy+6-2x-3y= 4.鍥犲紡鍒嗚Вx2(x-y)+y2(y-x)= 5.鍥犲紡鍒嗚В2x2-(a-2b)x-ab= 6.鍥犲紡鍒嗚Вa4-9a2b2= 7.鑻ュ凡鐭3+3x2-4鍚湁x-1鐨勫洜寮,璇曞垎瑙3+3x2-4= 8.鍥犲紡鍒嗚Вab(x2-y2)+xy(...
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绛旓細BC路AC=m(m-2)鍙圓B涓篟t鈻矨BC鐨勬枩杈癸紝BC銆丄C涓虹洿瑙掕竟 鈭碅B²=BC²+AC²=(BC+AC)²-2BC路AC=4(m-1)²-2m(m-2)=2m²+4m+4=10 鈭磎²+2m-3=0 瑙ｅ緱m=1鎴杕=-3 鑰屸柍=[2(m-1)]²-4m(m-2)=4 鏁呮弧瓒抽鎰忕殑m鍊间负-3鎴1 ...
