how to calculate the MLEs of the 5 parameters of a bivariate normal population, the parameters being $\displaystyle \mu_x,\mu_y,\sigma_x,\sigma_y,\rho$?

while trying to solve for $\displaystyle \mu_x$, i got the following equation

$\displaystyle \sum{\frac{(x-\mu_x)}{\sigma_x^2}} = \rho\sum{\frac{(y-\mu_y)}{\sigma_x\sigma_y}}$

is this correct? how can i solve for $\displaystyle \mu_x$ from here?