Question: Solving multiple equations for one variable

den1 := (1/2)*((2+x^2)*sqrt(4+x^2)+2*sqrt(4+x^2)*cos(t*sqrt(4+x^2)*tau/`ℏ`)+sqrt(4+x^2)*(cos(t*x*tau/`ℏ`))(2+(2+x^2)*cos(t*sqrt(4+x^2)*tau/`ℏ`))+x*(4+x^2)*sin(t*x*tau/`ℏ`)*sin(t*sqrt(4+x^2)*tau/`ℏ`))/(4+x^2)^(3/2)

den2 := 4*cos((1/2)*t*x*tau/`ℏ`)^2*sin((1/2)*t*sqrt(4+x^2)*tau/`ℏ`)^2/(4+x^2);

den3 := 4*sin((1/2)*t*x*tau/`ℏ`)^2*sin((1/2)*t*sqrt(4+x^2)*tau/`ℏ`)^2/(4+x^2);

den4 := (1/2)*((2+x^2)*sqrt(4+x^2)+2*sqrt(4+x^2)*cos(t*sqrt(4+x^2)*tau/`ℏ`)-sqrt(4+x^2)*(cos(t*x*tau/`ℏ`))(2+(2+x^2)*cos(t*sqrt(4+x^2)*tau/`ℏ`))-x*(4+x^2)*sin(t*x*tau/`ℏ`)*sin(t*sqrt(4+x^2)*tau/`ℏ`))/(4+x^2)^(3/2);

After definining these equations, I wish to do the following:

solve({den1 = 0, den2 = 0, den3 = 0, den4 = 1}, x)

But I get the following prompt:

Warning, solutions may have been lost

I'm only looking REAL values of x and t - also, what do I do to make the command solve for values of t as well?

I've already done this with Mathematica but I don't know how to find all possible solutions.

Can anyone help me?