Find the exponential function

Question

f(x)=a^x whose graph goes through the point (2,25)

 

a=___

Answer 1

When you are given the coordinates of a point like (2,25) then the first value represents the x-coordinate and the second value represents the y-coordinate  

 

f(x) is just another way of writing y  

 

So plug in 2 for x and 25 for f(x) and then solve for a  

 

One more thing you might find useful - exponential functions can only have positive bases.  So if you get to a point where you have a choice between a positive and a negative value for a then you can discard the negative one.  

Answer 2

y=5^x will pass through (2,25)