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Ryandmitri
- Junior | Next Rank: 30 Posts
- Posts: 29
- Joined: Sun Jan 16, 2011 10:45 pm
Dear All,
From what I understand, if one comes across the equation(x^2) = 4, then x = +2 or -2. However √(4) = +2 only (not -2).
I came across a question which required me to find a value for the following equation : √(x^2 - 6x + 9) + √(2 - x) + x - 3. To be precise, the question was as follows :
If each expression under the square root is greater than or equal to 0, what is √(x^2 - 6x + 9) + √(2 - x) + x - 3?
a. √(2-x)
b. 2x - 6 + √(2-x)
c. √(2-x) + x - 3
d. 2x - 6 + √(x-2)
e. x + √(x-2)
Now if the first square root is taken into consideration, √(x^2 - 6x + 9) = √(x-3)^2. So shouldnt the solution for this be +(x-3) as well as - (x-3). But while solving this problem only the positive root was taken into consideration. I am confused as to when we need to consider both roots and when only the +ve root is to be considered.
From what I understand, if one comes across the equation(x^2) = 4, then x = +2 or -2. However √(4) = +2 only (not -2).
I came across a question which required me to find a value for the following equation : √(x^2 - 6x + 9) + √(2 - x) + x - 3. To be precise, the question was as follows :
If each expression under the square root is greater than or equal to 0, what is √(x^2 - 6x + 9) + √(2 - x) + x - 3?
a. √(2-x)
b. 2x - 6 + √(2-x)
c. √(2-x) + x - 3
d. 2x - 6 + √(x-2)
e. x + √(x-2)
Now if the first square root is taken into consideration, √(x^2 - 6x + 9) = √(x-3)^2. So shouldnt the solution for this be +(x-3) as well as - (x-3). But while solving this problem only the positive root was taken into consideration. I am confused as to when we need to consider both roots and when only the +ve root is to be considered.
