Look to see how did this one.......http://web2.0calc.com/questions/a-pair-of-points-on-the-graph-of-an-exponential-function-is-given-find-a-formula-for-the-function
Look to see how did this one.......http://web2.0calc.com/questions/a-pair-of-points-on-the-graph-of-an-exponential-function-is-given-find-a-formula-for-the-function