How can I get the slope from the following data:

I need to get the slope from ColumnC, from date 1/6/2010 to 1/8/2010.

using as "y axis" the dates and "x axis" the values in ColumnC

any Possible solution.?



ColumnA ColumnB ColumnC
1/5/2010 234 487
1/6/2010 456 898
1/6/2010 789 998
1/6/2010 123 123
1/7/2010 345 984
1/7/2010 678 783
1/7/2010 897 234
1/8/2010 098 543
1/8/2010 738 928
1/9/2010 123 123
1/9/2010 421 987