8 đề kiểm tra chương 1- Đại số 8

 8 Đề Kiểm tra Chương 1- Đại số 8
Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
Đề 1.
1.Viết bảy hằng đẳng thức đáng nhớ.
2Điền dấu ‘X’ vào ô thích hợp.
Câu
Nội dung
Đúng
Sai
1
(a – b )( b – a ) = ( a – b )2
2
-x2 + 6x – 9 = - ( x – 3 )2
3
-16x + 32 = -16( x + 12 )
4
-( x – 5 )2 = ( 5 – x )2
3. Rút gọn các biểu thức sau:
a. A= (x+y)2 + (x-y)2- 2(x+y)(x-y)
b. B= (x2-1)(x+2) - (x-2)(x2+ 2x+ 4)
4. Phân tích các đa thức thành nhân tử.
a.xy + y2 – x - y
b.25 - x2 - 4xy - 4y2
c. x2 - 4x + 3
5. Làm phép chia.
(x4 – x3 - 3x2 + x + 2): (x2 - 1)
6. Chứng minh : x 2– x + 1 > 0 Với mọi số thực x
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Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
Đề 2:
1.Khi nào đơn thức A chia hết cho đơn thức B.
Cho ví dụ.
2. Điền dấu ‘X’ vào ô thích hợp.
Câu
Nội dung
Đúng
Sai
1
(x - 2)2 = x2 – 2x + 4
2
(a - b)2= a2 – b2 
3
-(x + 3)3 = (-x - 3)3
4
(x3 - 8 ):(x - 2)= x2+2x + 4
3.Rút gọn rồi tính giá trị của biểu thức sau tại x = 2 ; y = -3
3(x – y)2 - 2(x + y)2- (x - y)(x + y)
4.Tìm x biết:
a. x 2– 49 = 0
b. x2 + x – 6= 0
5.Phân tích các đa thức thành nhân tử.
y2(x - 1) – 7y 3+ 7xy3
6.Làm phép chia.
(x4 – 2x3 – 2x - 1) : (x2 - 1)
7.Tìm n để 2n2 + 5n – 1 chia hết cho 2n – 1
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Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
Đề 3:
1.Viết bảy hằng đẳng thức đáng nhớ.
Tính nhanh: 872 + 26.87 + 132
2.Rút gọn các biểu thức sáu :
a) (2x + 1)2 + 2(4x2 - 1) + (2x - 1)2
b) (x2 - 1)(x + 2) – (x - 2)(x2 + 2x + 4)
3. Phân tích các đa thức sau thành nhân tử :
a) x2 – y2 – 5x + 5y
b) 5x3 – 5x2 y – 10x2 + – 10xy
c) 2x2 – 5x – 7
4. Làm phép chia 
(x4 – 2x3 + 4x2 - 8x) : (x2 + 4)
5. Chứng minh rằng x2 – 2x + 2 > 0 với mọi x
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Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
Đề 4:
1.Khi nào thì đa thức A chia hết cho đa thức B?
 Tìm n để A chia hết cho B, Biết A = - 6x ny7 ; B = x3 yn
2.Rút gọn các biểu thức sau:
a)(3x - 1)2 + 2(3x - 1)(2x + 1) + (2x + 1)2
b) (x2 + 1)(x - 3) – (x - 3)(x2 + 3x + 9)
3. Phân tích các đa thức sau thành nhân tử :
a) x3 – 3x2+ 1 – 3x b) 3x2 – 6xy + 3y2 - 12z2 c) 3x2 – 7x -10
4. Làm phép chia 
(x4 + 2x3 +10x - 25) : (x2 + 5)
5. Chứng minh rằng n4 + 2n3 – n2 – 2n chia hết cho 24 với mọi n 
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Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
Đề 5:
1.Phát biểu qui tắc nhân đa thức với đa thức.
2.Rút gọn các biểu thức sau:
a)(2x +3)2 + (2x + 5)2 - 2(2x +3)(2x + 5)
 b) (x -3)(x + 3) – (x - 3)2
3.Tính nhanh giá trị các biểu thức sau
a) 532 + 472 + 94.53 b) 502 – 492 + 482 – 472 + .+ 22 - 1 
4.Phân tích các đa thức sau thành nhân tử :
a) x4 + 1 – 2x2 b) 3x2 – 3y2 - 12x + 12y c) x2 – 3x + 2
5. Tìm số a để đa thức x3 -3x2 + 5x + a chia hết cho đa thức x – 2.
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Hä vµ tªn:......................... KiÓm tra ch­¬ng I
§¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
§Ò 6
Tr¾c nghiÖm.(2 ®)
 Bµi 1 ( 1 ®): §Ó biÓu thøc 9x2- 12x trë thµnh b×nh ph­¬ng cña mét ®a thøc cÇn ph¶i thªm sè nµo trong nh÷ng sè sau:
 A. 1 B. 4 C .9 D.16
Bµi 2 ( 1 ®): §¼ng thøc sau ®óng hay sai.
 A. (-a - b)2= a2 + b2 + 2ab B. ( - a + b)2 = a2 – 2ab + b2
 C. ( -a – b )( a - b) = b2 – a2 D. – ( a - b)2 = ( b - a) 2
PhÇn tù luËn
 Bµi 1( 3 ®) Lµm c¸c phÐp tÝnh sau:
 a) 4(x - 3y)(x + 3y) b) (2x - 5)2 + 3( x - 2)( x + 2) c) (x2+x -3)(x2-x + 3)
Bµi 2 ( 3 ®): Ph©n tÝch c¸c ®a thøc sau thµnh nh©n tö.
 a) xy – y2 – x + y b) 49 – x2 + 2xy – y2 c) 4x2 – 36x + 56
 Bµi 3 ( 2 ®) a) Thùc hiÖn phÐp chia ®a thøc: ( 6x3 + x2 – 29x + 21):(2x - 3)
 b) Chøng minh r»ng víi mäi n Z th× ( n4 + 2n3 – n2 - 2n )24
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§Ò 7
Hä vµ tªn:......................... KiÓm tra ch­¬ng I
 §¹i sè 8
§iÓm 
Lêi phª cña gi¸o viªn.
I. Tr¾c nghiÖm.(2 ®)
Bµi 1 ( 1 ®): CÇn ph¶i thªm vµo sè nµo trong nh÷ng sè sau ®Ó biÓu thøc x3 - 12x2 + 48 x trë thµnh lËp ph­¬ng mét hiÖu. 
 A. 1 B . 1 C. 64 D . - 64
Bµi 2 ( 1 ®): BiÓu thøc ( 3x + 1)3+ ( 2x - 3)3 sau khi thu gän cã hÖ sè cña x lµ 
 A. - 45 B. 45 C. 63 D.- 27
II.PhÇn tù luËn
Bµi 1( 3 ®) Lµm c¸c phÐp tÝnh sau:
( x - 3)( x2 + 3x + 9) - ( x3 + 3) 
( x - 1)( x2 + x + 1) – ( x + 1)( x - 1)
2 ( x - 1)2 – 2( x + 3 )( x - 3 )
Bµi 2 ( 3 ®): Ph©n tÝch c¸c ®a thøc sau thµnh nh©n tö.
a) xy + y2 – 3x – 3y b) 64 – ( x – 1 )3 c) 2x2 + 4x - 70
 Bµi 3 ( 2 ®): a) Thùc hiÖn phÐp chia ®a thøc: ( x3 + 2x2 – 22x + 21):(x - 3)
 b) Chøng minh r»ng víi mäi n Z th× ( n4 - 4n3 – 4n2 + 16n )384
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