问题 解答题
(1)(-3)2-(3.14-π)0+(-123
(2)(-2ab)(3a2-2ab-b2
(3) (2x-5)(2x+5)-(2x+1)(2x-3)
(4)(
x
3
+3)2-(
x
3
-3)2

(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+(-123=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)(

x
3
+3)2-(
x
3
-3)2=(
x
3
+3+
x
3
-3)(
x
3
+3-
x
3
+3)=12×
x
3
=4x;

(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.

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