Consider the diophantine equation in $\mathbb Z[x,y,z]$ in three integer variables $x,y,z$

$$x^2+L(y,z)x+L_1(y)L_2(z)=0$$ where $L(y,z)$ is a non-homogeneous linear polynomial in $y,z$ and $L_1(y),L_2(z)$ are linear non-homogeneous in $y,z$ respectively.

In general such an equation is difficult to solve if $x,y,z$ are independent.

However suppose that there are univariate linear non-homogeneous polynomials $L'(y)$ and $L''(z)$ such that if $(x^*,y^*,z^*)$ is a solution to the three variable diophantine equation then

1. $GCD(L'(y^*),L''(z^*)=1$

2. There exists integers $1<a,b$ with $a|L'(y^*)$ and $b|L''(z^*)$ such that $ab=x^*$

holds always. Then the unknown $x$ depends on $y,z$ and so in principle we should be able to eliminate $x$ and make this as a two variable quadratic diophantine equation.

1. One cannot say there is no small degree algebraic relation between $x$ and $y,z$ since we have already provided one by the quadratic equation. Unless we provide a different relation we cannot use elimination theory. However there is arithmetic relation. There is some hope. Is there a way to at least in principle reduce the problem to solving two unknowns through some functions coming from arithmetic?

2. What is the minimal degree of any other polynomial relation between $x,y,z$?


It is unclear if either of following two is possible at least when $L'(y)=L_1(y)$ and $L'(z)=L_2(z)$:

I. There is an explicit arithmetic function that relates $x$ and $y,z$.

II. There is any other low degree polynomial relation between $x$ and $y,z$. Note that by formulating the problem itself we have provided a quadratic relation between $x$ and $y,z$. So there is a polynomial relation. The problem is if there is another polynomial relation.