2006-09-27 13:43:42 · 6 answers · asked by J' K '06 1 in Science & Mathematics ➔ Mathematics
well dear;
f(x) = -x^3 + 9x
{ Factor '-x' }
f(x) = -x(x^2 - 9)
{ Watch out , x^ - 9 = ( x+3) ( x-3) }
f(x) = -x ( x+3)(x-3)
If u want to finds the roots ;
f(x) = 0
-x ( x+3)(x-3) = 0
Now;
- x = 0 ; x = 0
OR
x+3 = 0 ; x = -3
OR
x - 3 = 0 ; x = +3
Good Luck
2006-09-28 04:14:53 · answer #1 · answered by sweetie 5 · 1⤊ 1⤋
First factor out x
x(-x^2+9)
then use the special form of the difference of two squares
x(3+x)(3-x)
2006-09-27 20:47:36 · answer #2 · answered by notquiteme 2 · 0⤊ 0⤋
You can factor out x first, giving
x(9-x^2)
the 9-x^2 is equal to (3-x)(3+x) so the whole answer is
x(3-x)(3+x)
2006-09-27 20:45:55 · answer #3 · answered by spongeworthy_us 6 · 1⤊ 0⤋
-x^3 + 9x = -x(x^2 - 9) = -x(x - 3)(x + 3)
2006-09-27 21:45:44 · answer #4 · answered by Sherman81 6 · 0⤊ 0⤋
i think it would be prime because factoring cubes the number has to be a pefect cube an nine isnt a perfect cube...hope that helps
2006-09-27 20:48:00 · answer #5 · answered by Kiwi 1 · 0⤊ 0⤋
3x(-x^2+3)
2006-09-27 20:51:41 · answer #6 · answered by AG 2 · 0⤊ 0⤋