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sq root

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sq root

by CITI29 » Mon Jul 21, 2008 7:22 am
If sq rt((x+4)^2) = 3, which of the following could be the value of x – 4?

-Doesn't sq rt sign always denote positive value of the number? In that case wont the answer to above question be -5?..pls explain
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Re: sq root

by parallel_chase » Mon Jul 21, 2008 7:50 am
CITI29 wrote:If sq rt((x+4)^2) = 3, which of the following could be the value of x – 4?

-Doesn't sq rt sign always denote positive value of the number? In that case wont the answer to above question be -5?..pls explain
x-4 can either be -5 or -7

sq rt((x+4)^2) = 3 => (x+4)^2 = 9

x^2+8x+7=0

x=-1 or -7

x-4 = -5 or -7
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Re: sq root

by kris610 » Mon Jul 21, 2008 8:01 am
parallel_chase wrote:
CITI29 wrote:If sq rt((x+4)^2) = 3, which of the following could be the value of x – 4?

-Doesn't sq rt sign always denote positive value of the number? In that case wont the answer to above question be -5?..pls explain
x-4 can either be -5 or -7

sq rt((x+4)^2) = 3 => (x+4)^2 = 9

x^2+8x+7=0

x=-1 or -7

x-4 = -5 or -7

x-4 - -11 or x=-5.
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by sudhir3127 » Mon Jul 21, 2008 8:21 am
Answer can be -11 or -5
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Re: sq root

by parallel_chase » Mon Jul 21, 2008 9:59 am
kris610 wrote:
parallel_chase wrote:
CITI29 wrote:If sq rt((x+4)^2) = 3, which of the following could be the value of x – 4?

-Doesn't sq rt sign always denote positive value of the number? In that case wont the answer to above question be -5?..pls explain
x-4 can either be -5 or -7

sq rt((x+4)^2) = 3 => (x+4)^2 = 9

x^2+8x+7=0

x=-1 or -7

x-4 = -5 or -7

x-4 - -11 or x=-5.

yup made a silly mistake in writing.
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