we know that
We can enlarge or shrink the function in the y-direction by multiplying the function by a constant.
we have
[tex]y=a(b^{x})[/tex]
if [tex]a> 1[/tex] -------> the function enlarge
if [tex]0< a < 1[/tex] -------> the function shrinks
case A) [tex]a=4/5[/tex]
[tex]0 < (4/5)< 1[/tex] ------> the function shrinks
case B) [tex]a=5/4[/tex]
[tex](5/4)> 1[/tex] ------> the function enlarge
case C) [tex]a=3/2[/tex]
[tex](3/2)> 1[/tex] ------> the function enlarge
case D) [tex]a=7/4[/tex]
[tex](7/4)> 1[/tex] ------> the function enlarge
therefore
the answer is
[tex]a=4/5[/tex]
