Answer:
a = 4, b = 5
Step-by-step explanation:
Given the exponential function
f(x) = a[tex]b^{x}[/tex]
Use the given points to find a and b
Using (0, 4 ) , then
4 = a[tex]b^{0}[/tex] ( [tex]b^{0}[/tex] = 1 ) , thus
a = 4 , so
f(x) = 4[tex]b^{x}[/tex]
Using (1, 20 ) , then
20 = 4b ( divide both sides by 4 )
b = 5