Answer:
a = 37
Step-by-step explanation:
We can formulate the equation:
f(a) = 12a + 200 // Let a be the number of albums sold and f(a) be the amount of money made.
We know that The total made $644 so we have the equation:
644 = 12a + 200
-200 -200
444 = 12a
444/12 = a
a = 37