# Write an exponential equation from this data (data table included)

 Math Emeritus Sci Advisor Thanks PF Gold P: 39,304 There are two unknown constants in your formula, a and b. You need two equations to solve for two unknowns so pick two points (typically, it is best to endpoints, here 1954 and 1994). That will give you $$132459= ab^{1954}$$ and $$514013= ab^{1994}$$ It should be easy to see that dividing one equation by the other will eliminate a, leaving a single equation to solve for b.