Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: √ ∞ ≠ ≤ ≥ ≈ ⇒ ∈ Δ θ ∴ ∑ ∫ π -

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Topic review (newest first)

bobbym
2012-12-20 20:31:14

Hi;

Yes, it always takes the principal value.

anonimnystefy
2012-12-20 20:25:17

Even when you got √2x-1 = -8 you could've said that there are no solutions, because a square root of a positive number is always positive...

bob bundy
2012-12-20 19:45:43

hi Frublox

That answer is the solution to

-12 + √(2x-1) = -4

When you square you cannot help but introduce 'solutions' to this alternative equation as well so you were right to check the value you had.

Bob

bobbym
2012-12-20 13:21:46

Hi Frublox;

That is correct, there are no solutions. Not every equation is a true statement. You always check the validity of your answer by plugging into the original equation.

Please go here:

http://www.mathsisfun.com/algebra/radic … lving.html

Frublox
2012-12-20 12:01:58

Got this problem on a test:
          ____
12 + √2x-1 = 4

Okay, so then I subtract 12 from both sides:
  ____
√2x-1 = -8
2x - 1 = 64   I then square both sides...
2x = 65        Add 1 to each side
x = 65/2       Divide both sides by two.

However, that answer doesn't work. Are there simply no solutions, then?

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