+40 Find the value of r so the line that passes through each pair of points has the given slope: (r,5) (-2,4) m=-2/9
+36916 Find the slope between the lines (y1-y2) / (x1-x2) and this = - 2/9
(5-4) / (r - - 2) = -2/9
1/(r+2 ) = -2/9 you should be able to solve for 'r' from this.... 
