Answer
f(1)=9
Step-by-step explanation:
given f(a)=2*5^a-1..............(1)
f(a)=[tex]2\times5^a[/tex]-1
put a=1 in equ (1)
f(a)=[tex]2\times5^1[/tex]-1
f(1)=[tex]2\times5[/tex]-1
f(1)=10-1=9
f(1)=9 answer
