Question

A curve has equation y = 2$x^{2}$-3 FIND the set of values of x for which y>9

Answer 1

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Answer:

  x < -√6  or  √6 < x

Step-by-step explanation:

You want ...

  2x^2 -3 > 9

  2x^2 > 12 . . . . . add 3

  x^2 > 6 . . . . . . . divide by 2

  |x| > √6 . . . . . . . take the square root

This resolves into two disjoint sets:

  x < -√6  or  √6 < x

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In set notation, this might be ...

  {x | x < -√6 ∪ √6 < x}