I finalized the question into 2 equations:

$\displaystyle -xcos70+ycos50-5.4=0$...a

$\displaystyle xsin70+ysin50-23.9=0$...b

Just wondering, for a highschool grade 6th student or a first year university student, what is the fastest way to solve for $\displaystyle x$ and $\displaystyle y$?

I used matrix but it does not seem to be ideal, please see attachment.