3x+4y=47
X and y are integer solutions: when x= 1, y= 1 1.
When x=3 and y=8.
When x=9 and y=5.
When x= 13, y=2.
Therefore, there are four methods.
17, the method is the same as 16.
2 yuan banknotes and 5 yuan banknotes ***26-8= 18 (yuan)
According to the meaning of the question: 2x+5y= 18.
X and y are integer solutions: so there is and only if x=4 and y=2.
So the answer is: x=4 y=2.