When x = 0, y = 5.
When x = 2 and y = 4.
……
(2) (50-5x3)/ 10 = 3.5, so it is impossible.
(3) According to (1) the actual situation in life * * * are:
0,5
2,4
4,3
6,2
8, 1
10,0
* * * Six ways to change.