
Step-by-step solution:
Notice from the given figure that the graph of the function passes through points:
(0,9),(1,5)
The given graph resembles the Exponential Decay Function:
There is a Horizontal Asymptote at y=1.

approaches as values of are approaching or
, then the line
is a horizontal asymptote of the graph of the function.
If f(x) approaches c as values are approaching minus infinity or plus infinity, then the line y=c is a horizontal asymptote of the graph of the function.
The general form of the exponential function is:
y=a\cdot b^x+k
Here k is the horizontal asymptote, a is greater than 0 and b is the decay factor.
k is the horizontal asymptote,
It means,
k=1
{y}=ab^{x}+\textcolor{primary}{k}
Substitute k=1 into the above equation:
{y}=ab^{x}+\textcolor{primary}{1}
Substitute (x, y)=(0,9) into the equation:
{9}=ab^{0}+{1}
After simplifying:
{9}=ab^{0}+{1}\implies9=a+1\implies a=9-1=8
The value of a is 8:
Substitute (x, y)=(1,5) into the equation:
\textcolor{secondary}{5}=ab^{1}+1
Substitute the a=8 into the above:
5=(8)b+1\implies 8b=5-1\implies b=\frac{4}{8}=\frac{1}{2}
The value of b is 1/2:
Substitute the a=8, b=1/2 into the above:
y=8\cdot(\frac{1}{2})^x+1
The equation of the above graph is:
y=8\cdot(\frac{1}{2})^x+1
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