I have this function of order $4$ in $x$ for $-infty<x<+infty$

$$Big((5 x^2-3) sinh ;(5 x)Big)^2-Big(3 (2 x^2+1) tanh ;(-x)Big)^2$$

Now, since the function is even, and since the functions $sinh(x)$ and $tanh(x)$ are not periodic, can we claim that it is obvious that the function has $4$ real roots, $2$ of them positive, and two of them negative?