gijeqkeij,
I know it's not possible to have LaTeX, or even any semblance of formatting, for usernames, but one can in posts. Perhaps it might be better to answer OP's questions with better formatting for equations.
Gravitational field equations are:
G_{ij} = kT_{ij}
There's only one equation there, I hear you say. So why did I use the plural "equations" above? Well, i,j=1,2,3,4, so there are 16 equations.
There's lots more about this equation, and what it actually means (and what k is), in all kinds of books and websites. So I won't comment here. In fact, I'm not even sure who I've really addressed this to. I know it says gijeqkeij at the top, but he/she is presumably familiar with all this already. In any case, I've typed it, so I'll post it.