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Quadratic inequality-interval notation

  1. Jun 21, 2011 #1
    quadratic inequality--interval notation..

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

    Solve inequality and put into interval notation

    2. Relevant equations

    interval notation

    3. The attempt at a solution
    I don't even know where to start. I set it equal to zero -2x^2-x+10=0
  2. jcsd
  3. Jun 21, 2011 #2


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    Homework Helper

    Re: quadratic inequality--interval notation..

    It's fine to start by solving the corresponding equation. The solutions of the equation become "boundaries," if you will, of sets of numbers that are solutions to the inequality. Suppose there are two solutions, a & b, with a < b. Then you would have 3 potential range of numbers to test.

    Pick a value less than a and test into the original inequality. If the result is a true statement, then x < a would be in the solution set.

    Then pick a number between a and b and test. If it works, then a < x < b is in the solution set.

    Finally, pick a number in greater than b. If it works, then x > b is in the solution set.
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