Calculate the leading coefficient from one ordered pair by substituting the values into the exponential equation. For example, if your data has the ordered pair of (0,2), 2=ab^0 = a(2) = a. Therefore, your leading coefficient is 2.
Substitute another known data point into your new equation and solve for the base, b. In this example, the equation so far is y=(2)b^t. Substitute a new known "t" into the equation -- any point on your ordered pair data will do -- and it becomes:
y=(3)-b^1
3=-b^1=-b=3
b=-3
Write your equation with the leading coefficient from Step 1 and base from Step 2. In this example, the equation is:
y=(2)-3^t