Question 282706
Your problem makes no sense.
Perhaps you mean 
"If I have two points (-5,2) and (4,1), what is an equation in slope intercept form y=mx+b?"
y-y=m(x-x)
2-1=m(4-(-5))
1=m*9
m=1/9
y=mx+b
1=1/9*4+b
1=4/9+b
5/9=b
y=x/9+5/9