Algebra
posted by Anne .
find the value of r so that the line that passes through each pair of points has the given slope
(r,4), (7,1), m=

You didn't state the slope.
what ever it is ...
(41)/(r7) = m
m(r7) = 3
mr  7m = 3
mr = 3 + 7m
r = (3+7m)/m
so whatever m is, just plug it into that expression.
or
suppose the given m = 3/4
then (41)/(r7) = 3/4
3r  21 = 12
3r = 33
r = 11
Use the above method with your given slope, should be easy.