Kiểm tra Đại số 8 chương III

Hä vµ tªn :…………………….. KiÓm tra ch­¬ng III
Líp: …………………………..

§iÓm




Lêi phª cña c« gi¸o


§Ò bµi:
C©u 1 (3 ®iÓm) : Em h·y chän c©u tr¶ lêi ®óng trong c¸c ®¸p ¸n A, B, C, D
1/ Hai ph­¬ng tr×nh nµo t­¬ng ®­¬ng:
A. 4x + 3 = 0 vµ 4x2 + 3 = 0 B. 
x = 0 vµ
x = x
C. x + 1 = x vµ x + 1 = x + 1 D. x2 + 3 = 0 vµ (x2 + 3).(x – 5) = 0
2/ Ph­¬ng tr×nh 3x + m = x -1 nhËn x = -3 lµ nghiÖm, m cã gi¸ trÞ b»ng bao nhiªu?
A. 13 B. -13 C. 5 D. -5
C©u 2 (4 ®iÓm) : Gi¶i c¸c ph­¬ng tr×nh:
a/
+
= 2,5 x – 1
b/
+
=

C©u 3 (3 ®iÓm) : Mét ng­êi ®i xe ®¹p tõ A ®Õn B víi vËn tèc trung b×nh 15km/h. Lóc vÒ ng­êi ®ã chØ ®i víi vËn tèc trung b×nh 12km/h nªn thêi gian vÒ nhiÒu h¬n thêi gian ®i lµ 45 phót. TÝnh ®é dµi qu·ng ®­êng AB.
Bµi lµm
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