algebra, 11/27

a-c block:   1) m214, # 15-20
                  2) m214, # 21-26 (table and graph)
                  3) m215, # 36-42 (table and graph)

d-block:   1) m230, #20-25 (rise/run),  # 26-31 ( y2-y1/x2-x1)
                2) m231, # 38-42, 47-54