ANSWER
y=7
EXPLANATION
The horizontal asymptote of an exponential function
[tex]f(x)= a {(b)}^{x} + c[/tex]
is y=c.
The given exponential function is
[tex]f(x)= 4 {(52)}^{x} + 7[/tex]
When we compare to
[tex]f(x)= a {(b)}^{x} + c[/tex]
c=7, therefore the horizontal asymptote is y=7.
