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What is the solution to the equation 2*x^3-21*x^2+73*x-84 = 0

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tonyah995 | Student, Undergraduate | Salutatorian

Posted September 9, 2011 at 3:20 AM via web

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What is the solution to the equation 2*x^3-21*x^2+73*x-84 = 0

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted September 9, 2011 at 3:26 AM (Answer #1)

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We have to solve the equation: 2*x^3-21*x^2+73*x-84 = 0

2*x^3-21*x^2+73*x-84 = 0

=> 2x^3 - 6x^2 - 15x^2 + 45x + 28x - 84 = 0

=> 2x^2(x - 3) - 15x(x - 3) + 28(x - 3) = 0

=> (2x^2 - 15x + 28)(x - 3) = 0

=> (2x^2 - 8x - 7x + 28)(x - 3) = 0

=> [2x(x - 4) - 7(x - 4)](x - 3) = 0

=> (2x - 7)(x - 4)(x - 3) = 0

2x - 7 = 0

=> x = 3.5

x - 4 = 0

=> x = 4

x - 3 = 0

=> x = 3

The solution of the given equation is (3, 3.5, 4)

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