The values that would satisfy this equation are a = 4 and b = [tex] \sqrt{\frac{1}{5}} [/tex].
In order to solve this, we'll start by plugging in the second ordered pair into the base equation.
y = ab^x
4 = ab^0 ----> any number raised to the 0 equals 1.
4 = a(1)
4 = a
Now that we know a, we can use the first ordered pair and the a value to solve for b.
y = ab^x
20 = 4b^-2
20 = [tex] \frac{4}{b^{2}} [/tex]
b^2 = 4/20
b^2 = 1/5
b = [tex] \sqrt{\frac{1}{5}} [/tex]
