DAI 8

<span class='text_page_counter'>(1)</span>Hä vµ tªn : .. . .. . . . . . . . . . . . .. . . .. . . . Líp : 8 . . . . . . . . .. bài kiểm tra 45 phút (đề a) M«n : §¹i sè Lêi nhËn xÐt cña gi¸o viªn. Trêng thcs thä Ngäc. §iÓm. PhÇn tr¾c nghiÖm(3.0 ®iÓm) C©u 1(1.5 ®iÓm). H·y dïng bót nèi c¸c biÓu thøc sao cho chóng t¹o thµnh hai vÕ cña hằng đẳng thức. (m+n)(m2-mn+n2) m2-n2 m3+3m2n+3mn2+n3 (m-n)(m2+mn+n2) (m+n)2 (m-n)2 (m-n)3 m2+2mn+n2 m3-n3 (m+n)3 m2-2mn+n2 m3-3m2n+3mn2-n3 (m-n)(m+n) m3+n3 Câu 2(1.5 điểm). Khoanh tròn vào chữ cái đứng trớc đáp án đúng. a/ KÕt qu¶ cña phÐp chia: ( 3x3-4x2+11x+10 ) : ( 3x+2 ) lµ: A. x2+3x+5 B. 3x2-2x+5 C. x2-2x+5 D. x2-2x-5 b/ Gi¸ trÞ cña biÓu thøc : 9x2-16y2 t¹i x=24 vµ y=18 lµ : A. 5364 B. 0 C. -72 D. 508 PhÇn tù luËn(7.0 ®iÓm) C©u 3(4.0 ®iÓm). Thùc hiÖn phÐp tÝnh : 1 2  3 2 2  x y  x  xy  y  2 3   a/ b/ (x+2)(x3+3x+1) 2 2 c/ ( 2x+y )( 4x -2xy+y ) d/ ( 8x3y2-6x4y5+3x2y2 ) : 4xy2 C©u4.(1.5 ®iÓm) Ph©n tÝch c¸c ®a thøc sau thµnh nh©n tö : a/ 9x2- y2- 4y- 4 b/ x2- x- 12 c/ 2x2y+2xy2-7x-7y C©u 5.(1.5 ®iÓm) T×m x biÕt : a/ x2-18x+81 = 0 b/ x2-3x+10 = 0 Bµi lµm(phÇn tù luËn) ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………….

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<span class='text_page_counter'>(3)</span> §iÓm. bài kiểm tra 45 phút (đề b) M«n : §¹i sè Lêi nhËn xÐt cña gi¸o viªn. PhÇn tr¾c nghiÖm Câu 1. Hãy dùng bút nối các biểu thức sao cho chúng tạo thành hai vế của hằng đẳng thøc. a3-3a2b+3ab2-b3 (a+b)(a2-ab+b2) a2-b2 a3+3a2b+3ab2+b3 (a+b)3 (a+b)2 (a-b)2 (a-b)3 (a-b)(a2+ab+b2) a3-b3 a3+b3 a2-2ab+b2 a2+2ab+b2 (a-b)(a+b) Câu 2. Khoanh tròn vào chữ cái đứng trớc đáp án đúng. a/ KÕt qu¶ cña phÐp chia: ( 3x3-4x2+11x+10 ) : ( 3x+2 ) lµ: A. x2+3x+5 B. x2-2x+5 C. 3x2-2x+5 D. x2-2x-5 b/ Gi¸ trÞ cña biÓu thøc : ( x+y)2- ( x2+y2 ) t¹i x= 19 vµ y= 1/19 lµ : A. 2 B. 0 C. – 72 D. 508 PhÇn tù luËn C©u 3. Thùc hiÖn phÐp tÝnh : 5 2  2 2 2  x y  x  xy  y  2 3   a/ b/ (x+3)(x3+4x+1) c/ ( 2x - y )( 4x2+2xy+y2 ) d/ ( 12x4y3- 6x3y2+3x2y2 ) : 4xy2 C©u4. Ph©n tÝch c¸c ®a thøc sau thµnh nh©n tö : a/ 9x2- 4y2-4y- 1 b/ x2- 3x+ 10 c/ 2x2y+2xy2+7x+7y C©u 5. T×m x biÕt : a/ x2-16x+64 = 0 b/ x2- x-12 = 0 Bµi lµm(phÇn tù luËn) ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………………………….

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