(1)(-x-y)(x-y)+(x+y)
2;
(2)(2a
6x
3-9ax
6)÷(3ax
3);
(3)(2x-5)(2x+5)-(2x+1)(2x-3);
(4)
(a2b)•(-2ab2)2;
(5)-2
3+8
-1×(-1)
3×(-
)
-2+7°;
(6)(2x-y+1)(2x+y-1);
(7)
(-2xy2+xy)÷(-xy);
(8)(a+2)(a
2+4)(a
4+16)(a-2);
(9)(x-y)
2(x
2+y
2)
2(x+y)
2;
(10)(5m
3n
2)
2•(-2m
2)
3•(-n
3)
4;
(11)(π-3)
0+(-0.125)
2009×8
2009;
(12)(2a
m-3b
n)(3a
n+5b
m);
(13)(
x+
y)(
x-
y)-(
x-
y)
2;
(14)(-2a
2+3a)-(a
2-2a+1);
(15)-2a(a
2b+a-1)
(16)[x
4y-2x
2(x
2-3xy
2)]÷(-2x
3)
(17)(2m+n)(3n+1)
(18)101
2(19)199×201
(20)2008
2(21)78
2(22)(a+b+1)(a+b-1)
(23)(a-b)(a+b)(a
2+b
2)
(24)(66x
6y
3-24x
4y
2+9x
2y)÷(-3x
2y).