Factor and find all solutions of 3x^3 - 6x^2 - 9x = 0
\[3x^3 - 6x^2 - 9x = 0\]
you can start off by factoring out the GCF 3x 3x^3 - 6x^2 - 9x = 0 3x(x^2 - 2x - 3) = 0 now factor x^2 - 2x - 3
So that would be 3x(x-1)^2 = 3
no you can't move that 3 over like that
and x^2 -2x doesn't factor to (x-1)^2
I used the completing the square method...
factor x^2 - 2x - 3 find two numbers that multiply to -3 and add to -2
I don't think there r any...
This is how i did it, \[3x^3-6x-9x=0\] \[3x(x^2-2x-2)=0\] \[3x(x^2-2x+1)= 2+1\] \[3x(x^2-2x+1)=3\] \[3x(x-1)^2 =3\] \[3x(x-1)=\pm \sqrt{3}\] \[3x(x)=1\pm \sqrt{3}\]
Then i got stuck there
sure there are: -3 and +1
-3 + 1 = -2 -3 * 1 = -3
since the two numbers are -3 and 1, this means x^2 - 2x - 3 factors to (x-3)(x+1)
3x^3 - 6x^2 - 9x = 0 3x(x^2 - 2x - 3) = 0 3x(x-3)(x+1) = 0 now use the zero product property
but how did u get the 3 because u get a radical if you find the square root of 3
in your steps, you factored 3x^3 - 6x^2 - 9x incorrectly
you should get 3x(x^2 - 2x - 3) NOT 3x(x^2 - 2x - 2)
also, I'm not completing the square. I'm simply factoring x^2 - 2x - 3
ooooohhhhhhh
Thanks lol it was just a silly mistake
you're welcome
Join our real-time social learning platform and learn together with your friends!