题目内容
(1)(2m-3)(2m+5)
(2)20052-2006×2004
(3)4(x+1)2-( 2x+5)(2x-5)
(4)(a+b)(a-b)(a2+b2)
(5)(8xy2-6x2y+4xy)÷(-2x)
(6)(a+b-c)(a+b+c)
(7)20012
(8)(x+2y-3)2.
(2)20052-2006×2004
(3)4(x+1)2-( 2x+5)(2x-5)
(4)(a+b)(a-b)(a2+b2)
(5)(8xy2-6x2y+4xy)÷(-2x)
(6)(a+b-c)(a+b+c)
(7)20012
(8)(x+2y-3)2.
(1)(2m-3)(2m+5)
=4m2+10m-6m-15
=4m2+4m-15;
(2)20052-2006×2004
=20052-(2005+1)×(2005-1)
=20052-20052+1
=1;
(3)4(x+1)2-( 2x+5)(2x-5)
=4(x2+2x+1)-(4x2-25)
=4x2+8x+4-4x2+25
=8x+29;
(4)(a+b)(a-b)(a2+b2)
=(a2-b2)(a2+b2)
=a4-b4;
(5)(8xy2-6x2y+4xy)÷(-2x)
=8xy2÷(-2x)-6x2y÷(-2x)+4xy÷(-2x)
=-4y2+3xy-2y;
(6)(a+b-c)(a+b+c)
=(aa+b)2-c2
=aa2+2aaba+b2-c2;
(7)20012
=(2000+1)2
=20002+2×2000×1+12
=4000000+4000+1
=4004001;
(8)(x+2y-3)2.
=(x+2y)2-2(x+2y)×3+32
=x2+4xy+4y2-6x-12y+9.
=4m2+10m-6m-15
=4m2+4m-15;
(2)20052-2006×2004
=20052-(2005+1)×(2005-1)
=20052-20052+1
=1;
(3)4(x+1)2-( 2x+5)(2x-5)
=4(x2+2x+1)-(4x2-25)
=4x2+8x+4-4x2+25
=8x+29;
(4)(a+b)(a-b)(a2+b2)
=(a2-b2)(a2+b2)
=a4-b4;
(5)(8xy2-6x2y+4xy)÷(-2x)
=8xy2÷(-2x)-6x2y÷(-2x)+4xy÷(-2x)
=-4y2+3xy-2y;
(6)(a+b-c)(a+b+c)
=(aa+b)2-c2
=aa2+2aaba+b2-c2;
(7)20012
=(2000+1)2
=20002+2×2000×1+12
=4000000+4000+1
=4004001;
(8)(x+2y-3)2.
=(x+2y)2-2(x+2y)×3+32
=x2+4xy+4y2-6x-12y+9.

练习册系列答案
相关题目