Unable to find explicit solution to a very simple equation

So my code is

syms x
solve(-3*x^4+12*x^2 > 0,x)

And for some reason matlab cant answer this. I have tried everything but nothing has worked so far

the answer should be x=0 and x=+-2, but instead i get

Warning: Unable to find explicit solution. For options, see help. 
 
ans =
 
Empty sym: 0-by-1
 
 

What am i doing wrong? I am losing my mind cause I know this is a very simple task

Answer 1

[Paul]

The equation in the question is an inequality, but the supposed solution posed in the question is for an equality:

syms x real
f(x) = -3*x^4 + 12*x^2;
solve(f(x)==0,x)

ans = 

Plot f(x)

fplot(f(x),[-2 2])

So that gives us an idea of what the solution should be for f(x) > 0.

assume(x,'real') % otherwise the solver will consider x as complex 
sol = solve(f(x)>0,'ReturnConditions',true);
sol.x

ans = 

sol.parameters

ans = 

x

sol.conditions

ans = 

Which looks like the expected solution based on the graph.

[Teemu Hämäläinen]

Thanks a million times! I wouldn't have figured it out on my own. It works now! <3