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If (x - 3)^2 = 225, which of the following could be the
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Re: If (x - 3)^2 = 225, which of the following could be
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carcass wrote:
If \((x - 3)^2 = 225\), which of the following could be the value of \(x + 3\) ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
Honestly carcass, that's a newbie mistake and you should not be making it!
\((x - 3)^2 = 15^2\)
When you take the root, you get
|x-3| = 15
and hence you get x = 18 or -12
Alternatively,
\((x - 3)^2 - 15^2 = 0\)
(x - 3 - 15)(x - 3 + 15) = 0
x = 18 or -12
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Re: If (x - 3)^2 = 225, which of the following could be
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carcass wrote:
If \((x - 3)^2 = 225\), which of the following could be the value of \(x + 3\) ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
both 18 and -12 satisfy the given equation
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Re: If (x - 3)^2 = 225, which of the following could be
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jbisht wrote:
carcass wrote:
If \((x - 3)^2 = 225\), which of the following could be the value of \(x + 3\) ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
both 18 and -12 satisfy the given equation
Posted from my mobile device hence, x+3 is 21 or -9
Posted from my mobile device
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Re: If (x - 3)^2 = 225, which of the following could be
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Re: If (x - 3)^2 = 225, which of the following could be
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carcass wrote:
If \((x - 3)^2 = 225\), which of the following could be the value of \(x + 3\) ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
Yes here are my two cents...
\((x - 3)^2 = 225\)
Since squaring on both sides leaves +/- \(x - 3 = +/- 15\)
This gives two eqns..
\(x - 3 = 15\)
\(x - 3 = -15\)
So, x= 18 means x+3=15
or
x=-12 means x+3=-9
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Re: If (x - 3)^2 = 225, which of the following could be
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VeritasPrepKarishma wrote:
carcass wrote:
If \((x - 3)^2 = 225\), which of the following could be the value of \(x + 3\) ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
Honestly carcass, that's a newbie mistake and you should not be making it!
\((x - 3)^2 = 15^2\)
When you take the root, you get
|x-3| = 15
and hence you get x = 18 or -12
Alternatively,
\((x - 3)^2 - 15^2 = 0\)
(x - 3 - 15)(x - 3 + 15) = 0
x = 18 or -12
No no .......you are perfectly right
.
maybe tired maybe stressed..........I know but you are right. Thanks
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Re: If (x - 3)^2 = 225, which of the following could be the
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One more method (This is time consuming)
Writing the equation as
x^2 - 6x + 9 - 225 = 0
x^2 - 6x + 9 - 216 = 0
(x-18) . (x+12) = 0
x = 18 OR x = -12
x+3=15 or x+3 = -9
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Re: If (x - 3)^2 = 225, which of the following could be the
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If (x - 3)^2 = 225, which of the following could be the
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x-3 = 15 So x=18 or x=-12
x+3=21 or x+3=-9 So Answer B
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Originally posted by
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Last edited by
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Re: If (x - 3)^2 = 225, which of the following could be the
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How we can confirm which answer to be considered?
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If (x - 3)^2 = 225, which of the following could be the
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Pm091989 wrote:
How we can confirm which answer to be considered?
Sent from my Redmi Note 3 using
GMAT Club Forum mobile app (x-3)^2= 225
(x-3)^2= 15^2
(x-3)= +15 or -15
x=18 or -12
now the question asks which could be the value of x+3
if x=18 ==> x+3=21 (could be)
if x=-12==> x+3= -9 (could be)
only-9 is available as an option.
If both -9 and 21 were available as individual options then the question would be wrong.
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Re: If (x - 3)^2 = 225, which of the following could be the
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carcass wrote:
If (x - 3)^2 = 225, which of the following could be the value of x + 3 ?
(A) -15
(B) -12
(C) -9
(D) 15
(E) 18
in this question if we take the square of both sides we have\(x - 3= 15\)so why the explanation says: \(x - 3 = 15\) and \(x - 3 = -15\) ?????
\(\sqrt{(x - 3)^2} = \sqrt{225}\)
Or, \(( x - 3 ) =\)
+ \(15\)
If x = +15
x - 3 = 15
Or, x = 18 so x + 3 = 21
If x - 3 = - 15
Or, x = -12 , so
x + 3 = -9 Hence, answer will be (C) -9
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Re: If (x - 3)^2 = 225, which of the following could be the
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carcass wrote:
If (x - 3)^2 = 225, which of the following could be the value of x + 3 ?
We can start by taking the square root of both sides of the equation (x - 3)^2 = 225.
√(x - 3)^2 = √225
x - 3 = 15 or x - 3 = -15
Thus, x = 18 or -12.
So possible values of x + 3 are as follows:
18 + 3 = 21
-12 + 3 = -9
Since -9 is the only answer within the answer choices, the answer is C.
Answer: C
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Re: If (x - 3)^2 = 225, which of the following could be the
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carcass wrote:
If (x - 3)^2 = 225, which of the following could be the value of x + 3 ?
(x - 3)^2 = 225
i.e. x-3 = +15 or -15
i.e. x = +18 or -12
i.e. x+3 = +21 or -9
Answer: option C
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