How do you find the m and b in the problem y=-x+1?

In Y=mx+b:

m=slope. That is found by using this formula y2-y1/x2-x1

b=y-intercept. That's found by finding slope, m, and substituting that into y=(m)x+b. Then you have to solve for b and that'll be your y-intercept. 

B.the point lies directly on the regression