If you have a lot of these to do, it is convenient to use a spreadsheet or other method of doing the computation.
The 2-point form of the equation for a line applies.
.. y = (y2 -y1)/(x2 -x1)*(x -x1) +y1
From this, you can determine that
.. m = (y2 -y1)/(x2 -x1)
and
.. b = y1 -x1*(y2 -y1)/(x2 -x1)
a) m = 15, b = -8
b) m = -2.5, b = 8
c) m = -1, b = 10
d) m = 3/4, b = -10
The attached graph shows the computation of m and b. The first point of each set is shown in purple, the second point is shown in red. You can see the line goes through the required points.
