Q: Solve the quadratic equation by factoring.
5x2 - 8 = 39x

A: 5x^2 - 8 = 39x; 5x^2 - 39x - 8 = 0; (5x + 1)(x - 8) = 0; 5x + 1 = 0; 5x = -1; x = -1/5; x - 8 = 0; x = 8 x = -1/5 or x = 8

Question

Asked 12/4/2012 12:57:30 PM

Updated 8/30/2014 6:22:45 PM

1 Answer/Comment

Flagged by andrewpallarca [8/30/2014 6:22:38 PM]

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3

5x^2 - 8 = 39x;

5x^2 - 39x - 8 = 0;

(5x + 1)(x - 8) = 0;

5x + 1 = 0; 5x = -1; x = -1/5;

x - 8 = 0; x = 8

x = -1/5 or x = 8

5x^2 - 39x - 8 = 0;

(5x + 1)(x - 8) = 0;

5x + 1 = 0; 5x = -1; x = -1/5;

x - 8 = 0; x = 8

x = -1/5 or x = 8

Added 8/30/2014 6:22:45 PM

This answer has been confirmed as correct and helpful.

12x^2 - 10x - 42 = 0

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Not Answered

Updated 7/30/2014 12:37:08 PM

1 Answer/Comment

12x^2 - 10x - 42 = 0

2(2x + 3)(3x - 7) = 0;

2(2x + 3) = 0; 4x + 6 = 0; 4x = -6; x = -6/4; x = -3/2

3x - 7 = 0; 3x = 7; x = 7/3

Solution: x = -3/2 or 7/3

2(2x + 3)(3x - 7) = 0;

2(2x + 3) = 0; 4x + 6 = 0; 4x = -6; x = -6/4; x = -3/2

3x - 7 = 0; 3x = 7; x = 7/3

Solution: x = -3/2 or 7/3

Added 7/30/2014 12:37:08 PM

This answer has been confirmed as correct and helpful.

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