Answer: a) y = 250(0.4)ˣ
b) 0.065536
Explanation:
Create a system of equations in the form y = a(b)ˣ
- where y is the Relative Brightness
- x is the Stellar Magnitude

Now insert b = 0.4 into one of the equations to solve for "a":

Now we have our equation for part (a) y = 250(0.4)ˣ
For part (b), replace the x with 9 and solve.
y = 250(0.4)⁹
= 0.065536