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If x is an integer, then how many values of x will satisfy the equatio [#permalink]
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Solution


Given:
    • We are given that x is an integer, and
    • We are also given an absolute value equation, |x + 2| = |3x + 14|

To find:
    • We need to find the number of values of x, that satisfy the given equation

Approach and Working:
    • In this question, we have modulus function on both sides of the equation.
    • Let’s first apply the definition to the LHS of the equation.
    • From this, we get,
      o x + 2 = |3x + 14|, if x ≥ -2, and
      o x + 2 = -|3x + 14|, if x < -2
    • Now, let’s consider the first case, x + 2 = |3x + 14|, if x ≥ -2. And, if we remove the modulus sign on the RHS of this equation, we get,
      o x + 2 = 3x + 14, if x ≥ -2 and x ≥ -14/3
         Solving this equation, we get, 2x = -12
         Implies, x = -6, which does not lie in the range
         Thus, x = -6 is not a possible value
      o x + 2 = -(3x + 14), if x ≥ -2 and x < -14/3
         This case is not possible as no value of x can simultaneously be ≥ -2 and < -14/3
    • Considering the second case, x + 2 = -|3x + 14|, if x < -2, and removing the modulus sign, we get,
      o x + 2 = -(3x + 14), if x < -2 and x ≥ -14/3
         Solving this equation, we get, 4x = -16
         Implies, x = -4, which lies in the range [-14/3, -2)
         Thus, x = -4 is a possible value of x[/list]
        o x + 2 = (3x + 14), if x < -2 and x < -14/3
           Solving this equation, we get, 2x = -12
           Implies, x = -6, which is less than both -2 and -14/3
           Thus, x = -6 is a possible value of x

Therefore, the only values of x, that satisfy the given equation, |x + 2|= |3x +14|, are -4 and -6

Hence, the correct answer is option C.

Answer: C


Originally posted by EgmatQuantExpert on 13 Sep 2018, 03:11.
Last edited by EgmatQuantExpert on 17 Sep 2018, 04:25, edited 1 time in total.
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Re: If x is an integer, then how many values of x will satisfy the equatio [#permalink]
Correct answer is B.

Solving the equation will yield two solutions , X=-6 and X=-3. Plugging these values into the equation will yield only 1 value to be valid, and that value is -6.
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Re: If x is an integer, then how many values of x will satisfy the equatio [#permalink]
TariqOmar wrote:
Correct answer is B.

Solving the equation will yield two solutions , X=-6 and X=-3. Plugging these values into the equation will yield only 1 value to be valid, and that value is -6.


But then don't you think the answer can be both 6 as well as -6? Since the equation is the mod of x? So I think the answer should be c!
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Re: If x is an integer, then how many values of x will satisfy the equatio [#permalink]
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'C' it is, squaring both sides.

x^2 + 4x + 4 = 9x^2 + 84x +196

8x^2 + 80x + 192 = 0

x^2 + 10x + 24 = 0

(x+6)(x+4)=0

x = -4, -6
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If x is an integer, then how many values of x will satisfy the equatio [#permalink]
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EgmatQuantExpert wrote:
Reserving this space to post the official solution


You made me remember my old school days

:lol: :lol: :lol:
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Re: If x is an integer, then how many values of x will satisfy the equatio [#permalink]
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Re: If x is an integer, then how many values of x will satisfy the equatio [#permalink]
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