Question 1185207
Plenty of this type have been solved here already.

Simple application for two-variable linear equation system



D price of drink
B price of burger

{{{system(7B+5D=28.5,6B+4D=23.98)}}}


Before either trying sub or elim method, look at what happens if you subtract equation 2 from equation 1   (and then use this whichever method you want to).