# College Algebra

posted by Edwin

3x^2-12x-24=0

1. helper

3x^2- 12x - 24 = 0

Solve the quadratic equation by completing the square:

Divide both sides by 3:
x^2 - 4x - 8 = 0
x^2 - 4x = 8
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)
x = 2 - 2 sqrt(3) or x - 2 = 2 sqrt(3)
x = 2 - 2 sqrt(3) or x = 2 + 2 sqrt(3)

2. sharlette

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

## Similar Questions

1. ### Algebra

Can someone please check my work for me. Q: Plot the graph of the equations 2x - 3y = 5 and 4x - 6y = 21 and interpret the result. A: 6(2x ¨C 3y = 5) = 12x ¨C 18y = 30 3(4x - 6y = 21) = 12x - 18y = 63 12x ¨C 18y = 30 + 12x - 18y …
2. ### algebra

5x -3 = 11 + 12x combine like figures add 3 to both sides to remove the 3 5x= 14+ 12x Now I get confused. If I remove the 12x I have to subtract 12x from 5x which gives me an answer of -7x=14 would the correct answer thus be x= -2?
3. ### algebra

24x^4-12x^3+48x^2/-4x 24x^4-12x^3+12(-1) 24x^4-12x^3+(-12x) 2x^4-12x^3-12x check this problem for me please
4. ### st paul (math college algebra)

rational expessions 7/3-8/12x-8
5. ### COLLEGE ALGEBRA

Solve by completing the square 12x^2+11x=5
6. ### COLLEGE ALGEBRA ..HELP!

Solve by completing the square 12x^2+11x=5
7. ### College algebra

Find the value of f(x) = -3x^2 + 12x-8

20x^2+12x