Posted by **Edwin** on Wednesday, February 2, 2011 at 9:19am.

3x^2-12x-24=0

- College Algebra -
**helper**, Wednesday, February 2, 2011 at 12:22pm
3x^2- 12x - 24 = 0

Solve the quadratic equation by completing the square:

Divide both sides by 3:

x^2 - 4x - 8 = 0

Add 8 to both sides:

x^2 - 4x = 8

Add 4 to both sides:

x^2 - 4x + 4 = 12

Factor the left hand side:

(x - 2)^2 = 12

Take the square root of both sides:

|x - 2| = 2 sqrt(3)

Eliminate the absolute value:

x - 2 = -2 sqrt(3) or x - 2 = 2 sqrt(3)

Add 2 to both sides:

x = 2 - 2 sqrt(3) or x - 2 = 2 sqrt(3)

Add 2 to both sides:

x = 2 - 2 sqrt(3) or x = 2 + 2 sqrt(3)

- College Algebra -
**sharlette**, Thursday, February 3, 2011 at 8:49am
A wheel made 672 revolutions at 35 1/5 revolutions per minute. How many minutes did it rotates?

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