Algebra II For Dummies, 2nd Edition
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Some algebraic equations that contain radicals call for more than one application of squaring both sides. For example, you usually need to square both sides more than once when you have three terms in the equation — two of them with radicals.

For example, say you have to work with the equation


Here's how you solve the problem:

  1. Move the radicals so that only one appears on each side.

  2. Square both sides of the equation.


    After simplifying the results of the first two steps, you have the following:

  3. Move all the nonradical terms to the left and simplify.

    This gives you

  4. Make the job of squaring the binomial on the left easier by dividing each term by two — the common factor of all the terms on both sides.

    You end up with


    which becomes

  5. Square both sides again, simplify, set the quadratic equal to zero, and solve for x.

    This process gives you the following:


    When x – 2 = 0, x = 2; and when x – 34 = 0, x = 34.

  6. Don't forget to check each solution in the original equation:


    The solution x = 2 works. The other solution, x = 34, doesn't work in the equation. The number 34 is an extraneous solution.

About This Article

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About the book author:

Mary Jane Sterling taught algebra, business calculus, geometry, and finite mathematics at Bradley University in Peoria, Illinois, for more than 30 years. She is the author of several For Dummies books, including Algebra Workbook For Dummies, Algebra II For Dummies, and Algebra II Workbook For Dummies.

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