TRƯỜNG TH - THCS LÊ KHẮC CẨN

KIỂM TRA TX ĐẠI SỐ 8

Hä vµ tªn HS: .........................................................

Líp 8.....

(Bµi sè 2).

Bài 1. Viết công thức và vận dụng cho các HĐT sau (2đ)
a, ( A + B)2 = ..................................................................... ( x + 3)2 = ...........................................................
b. ( A – B)2 = ............................................................. ( x – 5)2 = ..............................................................
c. A2 – B2 = ....................................................................... x2 – 92 = ............................................................
Bài 2. Vận dụng cho các HĐT sau (2đ)
a, ( 2x + 1)2 = ................................................................ ( 2x + 3y)2 = ........................................................
b. ( 3x – 2)2 = ............................................................. ( 3x – 2y)2 = ........................................................
c. x2 – 3 = .................................................................... 4 – x2 = ................................................................
Bµi 3. H·y ghÐp mçi c©u ë cét A víi mét c©u ë cét B ®Ó ®îc HĐT ®óng.( 2đ)
1.

Cét A
x2 + 2x + 4

Cét B
a. (x – 1)2

Nối

2.

x2 – 2x + 1.

b. (x – 2)2.

1 - ..................

3.

9x2 + y2 + 6xy.

d.

2 - ..................

4.

x2 – 4x + 4

e. (3x + y)2

3 - .................

g.

4 - ..................

x2 + 1
(x + 1)2

Bµi 4: §iÒn ®¬n thøc thÝch hîp vµo chç cã dÊu (.....) ®Ó ®îc c¸c HĐT ®óng. (2đ)
1/ x2 + 6xy + ....................

=(

....................+ .................... )2

2/ (.................... + 2).( .................... – 2) = a2 –
3/ y2 – 12y + ....................

=

4/ 4a2 + 2a +

= ( 2a +

....................

(....................

;

....................

–

.................... )2

.................... )2

Bµi 5. Trình bầy cách tính nhanh (2đ)
a. 992 = .......................................................................................................................................................................
b. 732 – 272 = ............................................................................................................................................................
c. 20052 =

..................................................................................................................................................................

d. 842 – 32.84 + 162 =
e. Cho x +

= 3 tính

.......................................................................................................................................

= ?.......................................................................................................................