College Algebra
posted by Edwin .
3x^212x24=0

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) 
A wheel made 672 revolutions at 35 1/5 revolutions per minute. How many minutes did it rotates?