Answer: m=1/2; b=-5
Explanation:
We can use the given points to find slope, then use the y=mx+b equation to find the y-intercept. The formula for slope is
.

Now that we know m=1/2, we can use that in y=mx+b to find the y-intercept. We can use any given point to plug into x and y.
y=1/2x+b [plug in x and y]
-2=1/2(6)+b [multiply]
-2=3+b [subtract both sides by 3]
b=-5
Now, we know that b=-5.