问题
解答题
(1)(-3)2-(3.14-π)0+(-12)3 (2)(-2ab)(3a2-2ab-b2) (3) (2x-5)(2x+5)-(2x+1)(2x-3) (4)(
(5)(x+1)(x+3)-(x-2)2 (6)(a+b+3)(a+b-3) (7)(9x2y-6xy2+3xy)÷( 3xy) |
答案
(1)(-3)2-(3.14-π)0+(-12)3=9-1+(-1)3=9-1-1=7;
(2)(-2ab)(3a2-2ab-b2)=-6a3b+4a2b2-+2ab3;
(3) (2x-5)(2x+5)-(2x+1)(2x-3)=4x2-25-4x2+4x+3=4x-22;
(4)(
+3)2-(x 3
-3)2=(x 3
+3+x 3
-3)(x 3
+3-x 3
+3)=12×x 3
=4x;x 3
(5)(x+1)(x+3)-(x-2)2=x2+4x+3-x2+4x-4=8x-1;
(6)(a+b+3)(a+b-3)=(a+b)2-9=a2+2ab+b2-9;
(7)(9x2y-6xy2+3xy)÷( 3xy)=3x-2y+1.
故答案为7、-6a3b+4a2b2-+2ab3、4x-22、4x、8x-1、a2+2ab+b2-9、3x-2y+1.