1) The answer is B because it goes through the cluster.
2) Now find the slope and the y intercept.
The slope = 1
Y intercept, where it croses y = 2
y = 1x + 2
3) Look where x = 50, and find y.
x = 50, y = 10
Answer: 10
4) The slope is 10, find two points on the line and calculate
m = y2 - y1/x2 - x1
m = 10
Now find where it crosses, this one is easy, it's 50.
Answer: y=10x+50