I'm out of practice with algebra, and I'm having a mind blank on how to solve for $t$ in the following equation. It's for some collision detection if you're wondering. $$\Bigl( \bigl(a-y-(qt)\bigr) \bigl(b-x-(rt)\bigr) \Bigr) - \Bigl( \bigl(c-x-(rt)\bigr) \bigl(d-y-(qt)\bigr) \Bigr) = z$$
I'm really not seeing it at the moment. Thanks for any help.