algebra, 12/12

a-c block:  m4.4b
                 #1-9 (use rise/run)
                 #10-18 (y2-y1)/(x2-x1)
                 #19-23 (solve like we did in class)

d-block:  1) b170,  # 4-6, 7-17 , (graph all problems using the slope and y-intercept)
               2) b171, # 18-23 (graph using slope and y-int)