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What is `int_(2)^9 3x^2 - 14x + 9 dx`

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xetaalpha2 | Student | Honors

Posted September 20, 2012 at 3:24 PM via web

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What is `int_(2)^9 3x^2 - 14x + 9 dx`

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted September 20, 2012 at 3:28 PM (Answer #1)

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The integral `int_(2)^9 3x^2 - 14x + 9 dx` has to be determined.

`int_(2)^9 3x^2 - 14x + 9 dx`

=> `(3x^3/3 - 14x^2/2 + 9x) _(2)^9`

=> `(x^3 - 7x^2 + 9x) _(2)^9`

=> `(9^3 - 7*9^2 + 9*9) - (2^3 - 7*4 + 18)`

=> 729 - 567 + 81 - 8 + 28 - 18

=> 245

The integral `int_(2)^9 3x^2 - 14x + 9 dx = 245`

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