# All square roots are either positive or negative

In the problem which I attempted today

√(x+1)-√(x-1) = √(4x-1)

the solution is 5/4

It is NOT insolvable, as given in the answer, because when put in as a check the result is

√(5/4+1)-√(5/4-1) = √(4*5/4-1) √(9/4) -√(1/4) = √(5-1) 3/2 +or- 1/2 = 2 Hence either 3/2 + 1/2 = 2 YES 3/2 - 1/2 = 2 NO Therefore the answer given is incorrect BECAUSE ALL SQUARE ROOTS ARE EITHER POSITIVE OR NEGATIVE

regards JR123

Note by John Rimmer
1 year, 5 months ago

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I believe you are referring to this problem.

The solution is not $$\frac{5}{4}$$.

The correct answer, as you pointed out, is "No solution".

In future, if you have any issues with a problem, you can report it directly by selecting "Report problem" from the menu. This will allow the problem creator to respond to you directly.

Staff - 1 year, 5 months ago

In solving Maths problems it is often necessary to discard a negative result and accept the positive one when two possibilities are found. I suggest you look at my analysis again.

- 1 year, 5 months ago