# Help with curve equation

A curve equation is y = 3x - x^3/2

find the value of X when y=0

thrill3rnit3
Gold Member

0 = 3x - x3/2
x3/2 = 3x

tell me if you still need help after that

0 = 3x - x3/2
x3/2 = 3x

tell me if you still need help after that

Yes infact its there that i am stuck..!!!!!!

0 = 3x - x3/2
x3/2 = 3x

tell me if you still need help after that
i want to know how to find the value of x

berkeman
Mentor

i want to know how to find the value of x

x3/2 = 3x

[STRIKE]Hint -- remember that in working with equations, you want to do the SAME thing to both sides of the equation, while working to simplify everything. What operation can you do to both sides of this equation to get rid of an x on both sides....?[/STRIKE]

EDIT -- oops, see better hint later by Mark44

Last edited:
thrill3rnit3
Gold Member

Don't forget the case x=0 though.

Mark44
Mentor

0 = 3x - x3/2
x3/2 = 3x

tell me if you still need help after that
Writing the equation as x3/2 = 3x is NOT a good strategy. Instead, work with x3 - 6x = 0 (equivalent to the one you started with) and factor the cubic expression.

thrill3rnit3
Gold Member

They both yield the same answers, except that you lose the solution x=0 if you do the first method. I'm sorry if I forgot to make that clear.

Mark44
Mentor

They both yield the same answers, except that you lose the solution x=0 if you do the first method. I'm sorry if I forgot to make that clear.
That's why factoring is a better strategy - you don't lose solutions.