1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Solve for X

  1. May 24, 2008 #1

    LLS

    User Avatar

    Did I do this problem correctly?

    1. The problem statement, all variables and given/known data

    The √ sign extends over x+3 only. Solve for x.

    √(x+3) + 3 = 9

    3. The attempt at a solution

    subtract 3 from each side

    √(x+3) = 6

    √(33 + 3) = 6

    √36 = 6

    x = 33
     
  2. jcsd
  3. May 24, 2008 #2

    Defennder

    User Avatar
    Homework Helper

    That's an odd way to solve it, but it's correct. To make things easier, you could square both sides of the equation [itex]\sqrt{x+3} = 6[/itex] and solve it easily.
     
  4. May 24, 2008 #3

    LLS

    User Avatar

    Thank you.

    I've been told that I am an odd person, LOL!!

    :)

    Have a safe weekend.
     
  5. May 24, 2008 #4
    Why did you input 33 as x? Well you get to the solution, but that's not how you should solve irrational equations.

    [tex]\sqrt{x + 3}[/tex] = 6

    Until here, everything is fine but then you have to square both sides and guarantee that the expression that is under the root is not negative (which now can be excluded because we clearly see that 6 is positive, otherwise if we had a variable there, for example [tex]\sqrt{x + 3}[/tex] = x + 2 can be solved by solving a system - ([tex]\sqrt{x + 3}[/tex])^2 = (x + 2)^2; x + 3 [tex]\geq0[/tex])

    So follows:

    x + 3 = 36
    x = 33


    I hope you can understand my explanation.


    EDIT: Too late
     
  6. May 24, 2008 #5

    LLS

    User Avatar

    I understand, thank you.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Solve for X
  1. Solve for x (Replies: 7)

  2. Solve for x (Replies: 19)

  3. Solve for x (Replies: 6)

  4. Solve for (x) (Replies: 3)

  5. Solve for x (Replies: 3)

Loading...