At a concession stand, three hotdogs and two hamburgers cost 8.50, two hotdogs and three hamburgers cost 9.00. what is the cost of one hamburger and one hotdog?

so far i have:
x=hotdog
y-hamburger
3x+2y=8.50
2x+3y=9.00
for the life of me i cannot remember any of the steps past that. any would be awesome.

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.