Does anyone have a solver for the system of equations :
$$ v_1=A+B- (c_5 a / c_1(c_8+ c_3c_5/c_1 )), $$
$$ v_2=Ae^{r_1 h }+Be^{r_2 h}- (c_5 a / c_1(c_8+ c_3c_5/c_1 )),$$
$$x_1=b-(1/c_1)(A(c_2+c_3/r_1)+B(c_2+c_3/r_2)),$$
$$ x_2=b+ah-(1/c_1)(Ae^{r_1 h}(c_2+c_3/r_1)+Be^{r_2 h}(c_2+c_3/r_2))$$
for unknowns $a, b, A, B$, and everything else known constants.
I think what you have to do to see the point clearly is to put $(A, B, a, b) = (X, Y, Z, W)$ and not mess things up with fixed values of the constants. With this and representing the constant values, let's say with $t_i$, you have the following simple system: $$X+Y+t_1Z=t_2\\t_3X+t_4Y+t_1Z=t_5\\t_6X+t_7Y+W=t_8\\t_9X+t_{10}Y+t_{11}Z+t_{12}W=t_{13}$$ or is you want (to see more clearly maybe) $$\begin{pmatrix}1&1&t_1&0\\t_3&t_4&t_1&0\\t_6&t_7&0&1\\t_9&t_{10}&t_{11}&t_{12}\end{pmatrix}*\begin{pmatrix}X\\Y\\Z\\W\end{pmatrix}=\begin{pmatrix}t_2\\t_5\\t_8\\t_{13}\end{pmatrix}$$ You solve this system and replace the corresponding values of the constants with which you end up.