SOLUTION: x cubed-5x=0 i tried to factor it out- x(x squared -5) but i dont know how I could get that to equal 0.

Algebra ->  Square-cubic-other-roots -> SOLUTION: x cubed-5x=0 i tried to factor it out- x(x squared -5) but i dont know how I could get that to equal 0.      Log On


   

Question 481249: x cubed-5x=0
i tried to factor it out- x(x squared -5) but i dont know how I could get that to equal 0.
Found 2 solutions by nerdybill, MathLover1:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
You were correct in your approach...
x%5E3-5x+=+0
x%28x%5E2-5%29+=+0
set each term (the "x" and the "x^2-5" to zero to get:
x^2-5 = 0
x^2 = 5
x = +-sqrt(5)
.
and, of course
x = 0
.
so, the solution set is:
x = {-sqrt(5), 0, sqrt(5)}

Answer by MathLover1(20855) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E3-5x=0

x%5E3-5x=0.......factor it out

x%28x%5E2-5%29=0...now you have a product of x and %28x%5E2-5%29 equal to 0
means if x=0, whole product is equal to 0...that is first solution
and, if x%5E2-5=0, whole product is equal to 0; so, find other two solutions
solve x%5E2-5=0 for x
x%5E2-5=0...->...x%5E2=5....->...x=+-sqrt%285%29
finally, roots are:
x=0
x=sqrt%285%29 or x=1.5
x=-sqrt%285%29 or x=-1.5