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