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Solve this equation using the quadratic formula: x^2 - 3x = 40

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kristenmarieb... | Student, Grade 10 | Valedictorian

Posted May 2, 2013 at 5:43 PM via web

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Solve this equation using the quadratic formula:

x^2 - 3x = 40

Tagged with algebra 2, math

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jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted May 2, 2013 at 6:25 PM (Answer #1)

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`x^2 - 3x = 40`

`x^2-3x-40 = 0`

 

Using quadratic formular;

`x = (-(-3)+-sqrt((-3)^2-4xx1xx(-40)))/(2xx1)`

 

`x = ((3)+-sqrt(169))/(2)`

 

`x = ((3)+sqrt(169))/(2) = 8`

`x = ((3)-sqrt(169))/(2) = -5`

 

So the answers are x = 8 and x = -5.

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