Exercise 111 Page 479

In an exponential function on the form $y=a{b}^x,$ the coefficient $a$ shows the function's $y\text{-}$intercept, while $b$ is the function's multiplier. Examining the diagram, we can determine the $y\text{-}$intercept directly.

Now we have half of what we need to write the equation. Finally, to find $b$ we have to substitute a point into the function that does not fall on either of the axis. From the diagram, we can identify such a point. When we know one more point on the function, we can substitute it into the function and solve for $b.$ Now we can complete the equation.