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Lisa solved 3x2 + 1 = 28 as shown. 3x2 + 1 = 28 3x2 = 27 x2 = 9 She concluded that the solutions to this quadratic equation are x = -9 or x = 9. Using a complete sentence, explain what mistake she made.
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Lisa solved 3x2 + 1 = 28 as shown.

3x2 + 1 = 28

3x2 = 27

x2 = 9

She concluded that the solutions to this quadratic equation are x = -9 or x = 9. Using a complete sentence, explain what mistake she made.

Please answer below

User Martin Kure
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1 Answer

7 votes

x squared = 9 NOT x

x = square roots of 9 which is +3 or -3.

User Drew Verlee
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