Since there is a common ratio of 7 between the y-values for « constant increase of 1 in the x-values, then the function is exponential.

Use the exponential model \(\displaystyle{y}={a}{b}^{{x}}\)

where a is the initial value (where x= 0) and & is the common ratio. Substitute a = 8 and b= 7 so: \(\displaystyle{y}={8}{\left({7}\right)}^{{x}}\)

or

\(\displaystyle{f{{\left({x}\right)}}}={8}{\left({7}\right)}^{{x}}\)