Values of an equation

Question

The graph of y = ab^x is decreasing and passes through the point (0,4). what values are possible for b?

Answer 1

y = ab^x

 

We can use the point (0,4) to tell us what a is but not b:

 

y = ab^x

4 = ab⁰

4 = a

 

y = 4b^x

 

Since y is decreasing, we have exponential decay which occurs for values of 0 < b < 1.