AMC10 2002 B
AMC10 2002 B · Q4
AMC10 2002 B · Q4. It mainly tests Rational expressions, Manipulating equations.
What is the value of $(3x -2)(4x + 1) - \frac{3x -2}{4x + 1}$ when $x = 4$?
当 $x = 4$ 时，$(3x -2)(4x + 1) - \frac{3x -2}{4x + 1}$ 的值是多少？
(A)
0
0
(B)
1
1
(C)
10
10
(D)
11
11
(E)
12
12
Answer
Correct choice: (D)
正确答案：（D）
Solution
(D) Since
$(3x-2)(4x+1)-(3x-2)4x+1=(3x-2)(4x+1-4x)+1$
$=(3x-2)\cdot1+1=3x-1,$
when $x=4$ we have the value $3\cdot4-1=11.$
（D）因为
$(3x-2)(4x+1)-(3x-2)4x+1=(3x-2)(4x+1-4x)+1$
$=(3x-2)\cdot1+1=3x-1,$
当 $x=4$ 时，其值为 $3\cdot4-1=11.$
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