You mistyped twice:
One of those - signs in both y-3/5x-1 and y-mx+b should be an =.
If you meant this system
,
then substitute 5 for x and 2 for y
There are lots of possibilities. Here are some:
m = -1, b = 7 y = -1x + 7, or just y = -x + 7
m = 0, b = 2 y = 0x + 2, or just y = 2
m = 1, b = -3 y = 1x - 3, or just y = x - 3
m = 2, b = -8 y = 2x - 8
Edwin