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If x ≠ 2.5 and 2x = |15 - 4x|, then x = ?

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by truplayer256 » Fri Sep 04, 2009 2:47 pm
2x=|15-4x|

Case 1:

-2x=15-4x

x=15/2=7.5

Case 2:

2x=15-4x

x=15/6=5/3

E
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by hansoo » Sat Sep 05, 2009 1:09 pm
Good work! The official answer is E.

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Re: If x ≠ 2.5 and 2x = |15 - 4x|, then x = ?

by Scott@TargetTestPrep » Sun May 10, 2020 11:26 am
hansoo wrote: ↑
Fri Sep 04, 2009 2:42 pm
 If x ≠ 2.5 and 2x = |15 - 4x|, then x =

a) 3.5
b) 4.5
c) 5.5
d) 6.5
e) 7.5
For this absolute value question, we must consider two cases: (1) when (15 - 4x) is positive and (2) when (15 - 4x) is negative.

Case 1. When 15 - 4x is positive, we have:

2x = 15 - 4x

6x = 15

x = 15/6 = 2.5

Case 2. When 15 - 4x is negative, we have:

2x = -15 + 4x

15 = 2x

7.5 = x

Since x is not 2.5, x must be 7.5.

Answer: E

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