3.解答题

(1)① 原式=a3b3ⅹa2b2ⅹa4b8c2=a9b12c2

②原式=-3x2y2+3x3y+6x3y4-3xy

③原式=a3-a+3a2-3-2a3+8a2+a-4=-a3+11a2-7

④原式=4m2-9n2

⑤原式=y4-9x4

⑥原式=(4x2-1)2=16x4-8x2+1

(2)①原式=(1000+3)(1000-3)=999991

②原式=2006/20062-(2006+1)(2006—1)=2006

(3) 原式=[x+(y+z)][x-(y+z)]=x2-(y+z)2=x2-y2-z2-2yz

(4)全对

(5)(x+y)2-(x-y)2=4xy

xy=[(2a)2-(2b)2]=a2-b2

(6) (a-1/a)2=a2+1/a2-2a 1/a

a2+1/a2=(a-1/a)2+2=16+2=18

(7) (a+b+c)2=a2+b2+c2+2ab+2ac+2bc

(2x-y+3z)2=4x2+y2+9z2-4xy+12xz-6yz

第57～59页

1选择题

(1)A(2)C(3)D(4)D(5)A(6)C(7)A (8)A (9)C (10)D(11)C

2.填空题

(1)5C (2)-3x2z (3)4×103 (4)15a3b2c (5)2(a+b)4 (6)6x2y2-1 (7)三次 (8)1 0 (9)a2b2

3.解答题

(1)①-1/2x2+3x-4.5 ②-2x2+3x-y ③3/2x2y+5xy2-9/2 (2)xm–n=xm÷xn=8÷5=1.6 (3)9n=32n=2 32m-4n+1=32m÷34n×3=(3 m) 2÷(32n)2 ×3=36÷4×3=27

(4)2x-1=0 (5)a8÷a5÷a (6)a=(25)11 b=(34)11 c=(43)11` ∵3211<6411<8111

x=0.5 =a2 =3211 =8111 =6411 ∴a

(7)x=1/2 原式=x3-x3+x4+1 当X=1/2时,原式=(1/2)4+1=17/16

=x4+1

(8)原式4a2-4a+1 当a=3/4时,

原式=4(3/4)2-4×3/4+1

=4×9/16-3+1

=9/4-2

=1/4