如题所述
第1个回答 2017-01-27
、(3a-7)(3a+7)-2a( -1) , 其中a=-3
22、[(3x- y 2)+3y(x- )] ÷[(2x+y)2-4y(x+ y)] ,其中x=-7.8, y=8 检举
回答人的补充 2009-08-17 09:12 (1).(x-1)-(2x+1)=-x-2
(2).3(x-2)+2(1-2x)=-x-4
(3).3(2b-3a)+3(2a-3b)=-3a-3b
(
4).(3x^2-xy-2y^2)-2(X^2+xy-2y^2)=(3x-y)(x+2y)-(x+2y)(x-y)=3y(x+2y)
(5)7a^b-(-4a^b+5ab^2)-2(2a^2b-3ab^2)=7a^b+4a^b-5ab^-4a^b+6ab^=-a^b+ab^=ab(b-a)
100×103×104 = ;②-2a3b4÷12a3b2 =
、(8xy2-6x2y)÷(-2x)=
、(a+2b-3c)(a-2b+3c)=[a+ ( )]·[a-( )]
、(-3x-4y) ·( ) = 9x2-16y2.
、(a+2b-3c)(a-2b+3c)=[a+ ( )]·[a-( )]
2(x3)2·x3-(2 x3)3+(-5x)2·x7
1.(2a+3b)*(2a-b)
2.(2x+y-1)的平方
解1.(2a+3b)*(2a-b) 用十字相乘法 吧
2 2 =4a2-3b2+4ab
3 -1
2.(2x+y-1)的平方 =4x2+y2+4xy +1-4x-2y
(3) 2(ab-3)(4)-3(ab2c+2bc-c) (5)(―2a3b) (―6ab6c) (6) (2xy2) 3yx
(1)2ab(5ab2+3a2b) (2)
三、巩固练习:
1、判断题:
(1) 3a3·5a3=15a3 ( )
(2) ( )
(3) ( )
(3) -x2(2y2-xy)=-2xy2-x3y ( )
2、计算题:
(3) (4) -3x(-y-xyz)
(5) 3x2(-y-xy2+x2) (6) 2ab(a2b- c)
(7) (a+b2+c3)·(-2a) (8) [-(a2)3+(ab)2+3]·(ab3)检举回答人的补充 2009-08-17 09:13 脱式计算: (15.6+9.744/2.4)*0.5
2.881/0.43-3.5*0.24
13.5*0.68/8.5
43.6-7.6*4.1
(86.9+667.6)/50.3
(73.5+80.5)/(10+12)
(7.8*15+5.1*10+6*5)/(15+10+5)
12.53-1.35*2-9.3
0.8*(4-3.75)/0.1
6-1.3*(10-7.3)
3/7 × 49/9 - 4/3
8/9 × 15/36 + 1/27
12× 5/6 – 2/9 ×3
8× 5/4 + 1/4
6÷ 3/8 – 3/8 ÷6
4/7 × 5/9 + 3/7 × 5/9
5/2 -( 3/2 + 4/5 )
7/8 + ( 1/8 + 1/9 )
9 × 5/6 + 5/6
3/4 × 8/9 - 1/3
7 × 5/49 + 3/14
6 ×( 1/2 + 2/3 )
8 × 4/5 + 8 × 11/5
31 × 5/6 – 5/6
9/7 - ( 2/7 – 10/21 )
5/9 × 18 – 14 × 2/7
4/5 × 25/16 + 2/3 × 3/4
14 × 8/7 – 5/6 × 12/15 17/32 – 3/4 × 9/24
3 × 2/9 + 1/3
5/7 × 3/25 + 3/7. 3/14 ×× 2/3 + 1/6
1/5 × 2/3 + 5/6
9/22 + 1/11 ÷ 1/2
5/3 × 11/5 + 4/3
45 × 2/3 + 1/3 × 15
7/19 + 12/19 × 5/6
1/4 + 3/4 ÷ 2/3
8/7 × 21/16 + 1/2
3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 – 3/8 ÷6
6. 4/7 × 5/9 + 3/7 × 5/9
7. 5/2 -( 3/2 + 4/5 )
8. 7/8 + ( 1/8 + 1/9 )
9. 9 × 5/6 + 5/6
10. 3/4 × 8/9 - 1/3
11. 7 × 5/49 + 3/14
12. 6 ×( 1/2 + 2/3 )
13. 8 × 4/5 + 8 × 11/5
14. 31 × 5/6 – 5/6
15. 9/7 - ( 2/7 – 10/21 )
16. 5/9 × 18 – 14 × 2/7
17. 4/5 × 25/16 + 2/3 × 3/4
18. 14 × 8/7 – 5/6 × 12/15
19. 17/32 – 3/4 × 9/24
20. 3 × 2/9 + 1/3本回答被网友采纳
22、[(3x- y 2)+3y(x- )] ÷[(2x+y)2-4y(x+ y)] ,其中x=-7.8, y=8 检举
回答人的补充 2009-08-17 09:12 (1).(x-1)-(2x+1)=-x-2
(2).3(x-2)+2(1-2x)=-x-4
(3).3(2b-3a)+3(2a-3b)=-3a-3b
(
4).(3x^2-xy-2y^2)-2(X^2+xy-2y^2)=(3x-y)(x+2y)-(x+2y)(x-y)=3y(x+2y)
(5)7a^b-(-4a^b+5ab^2)-2(2a^2b-3ab^2)=7a^b+4a^b-5ab^-4a^b+6ab^=-a^b+ab^=ab(b-a)
100×103×104 = ;②-2a3b4÷12a3b2 =
、(8xy2-6x2y)÷(-2x)=
、(a+2b-3c)(a-2b+3c)=[a+ ( )]·[a-( )]
、(-3x-4y) ·( ) = 9x2-16y2.
、(a+2b-3c)(a-2b+3c)=[a+ ( )]·[a-( )]
2(x3)2·x3-(2 x3)3+(-5x)2·x7
1.(2a+3b)*(2a-b)
2.(2x+y-1)的平方
解1.(2a+3b)*(2a-b) 用十字相乘法 吧
2 2 =4a2-3b2+4ab
3 -1
2.(2x+y-1)的平方 =4x2+y2+4xy +1-4x-2y
(3) 2(ab-3)(4)-3(ab2c+2bc-c) (5)(―2a3b) (―6ab6c) (6) (2xy2) 3yx
(1)2ab(5ab2+3a2b) (2)
三、巩固练习:
1、判断题:
(1) 3a3·5a3=15a3 ( )
(2) ( )
(3) ( )
(3) -x2(2y2-xy)=-2xy2-x3y ( )
2、计算题:
(3) (4) -3x(-y-xyz)
(5) 3x2(-y-xy2+x2) (6) 2ab(a2b- c)
(7) (a+b2+c3)·(-2a) (8) [-(a2)3+(ab)2+3]·(ab3)检举回答人的补充 2009-08-17 09:13 脱式计算: (15.6+9.744/2.4)*0.5
2.881/0.43-3.5*0.24
13.5*0.68/8.5
43.6-7.6*4.1
(86.9+667.6)/50.3
(73.5+80.5)/(10+12)
(7.8*15+5.1*10+6*5)/(15+10+5)
12.53-1.35*2-9.3
0.8*(4-3.75)/0.1
6-1.3*(10-7.3)
3/7 × 49/9 - 4/3
8/9 × 15/36 + 1/27
12× 5/6 – 2/9 ×3
8× 5/4 + 1/4
6÷ 3/8 – 3/8 ÷6
4/7 × 5/9 + 3/7 × 5/9
5/2 -( 3/2 + 4/5 )
7/8 + ( 1/8 + 1/9 )
9 × 5/6 + 5/6
3/4 × 8/9 - 1/3
7 × 5/49 + 3/14
6 ×( 1/2 + 2/3 )
8 × 4/5 + 8 × 11/5
31 × 5/6 – 5/6
9/7 - ( 2/7 – 10/21 )
5/9 × 18 – 14 × 2/7
4/5 × 25/16 + 2/3 × 3/4
14 × 8/7 – 5/6 × 12/15 17/32 – 3/4 × 9/24
3 × 2/9 + 1/3
5/7 × 3/25 + 3/7. 3/14 ×× 2/3 + 1/6
1/5 × 2/3 + 5/6
9/22 + 1/11 ÷ 1/2
5/3 × 11/5 + 4/3
45 × 2/3 + 1/3 × 15
7/19 + 12/19 × 5/6
1/4 + 3/4 ÷ 2/3
8/7 × 21/16 + 1/2
3/7 × 49/9 - 4/3
2. 8/9 × 15/36 + 1/27
3. 12× 5/6 – 2/9 ×3
4. 8× 5/4 + 1/4
5. 6÷ 3/8 – 3/8 ÷6
6. 4/7 × 5/9 + 3/7 × 5/9
7. 5/2 -( 3/2 + 4/5 )
8. 7/8 + ( 1/8 + 1/9 )
9. 9 × 5/6 + 5/6
10. 3/4 × 8/9 - 1/3
11. 7 × 5/49 + 3/14
12. 6 ×( 1/2 + 2/3 )
13. 8 × 4/5 + 8 × 11/5
14. 31 × 5/6 – 5/6
15. 9/7 - ( 2/7 – 10/21 )
16. 5/9 × 18 – 14 × 2/7
17. 4/5 × 25/16 + 2/3 × 3/4
18. 14 × 8/7 – 5/6 × 12/15
19. 17/32 – 3/4 × 9/24
20. 3 × 2/9 + 1/3本回答被网友采纳