Answer:
Amount of album solds= 37
Equation used: 12x+200=y
Step-by-step explanation:
The statement says that the artist earns 200 per month, and 12 by every album. (we call the amount of albums sold as 'x')
The total amount of money earn by the artist through that contract every month is 'y'
Hence y=12x+200
If the artist earned 644 in one month, it means that y=644 for that month.
Hence we have an equation.
644=200+12x
From this we can do the following,
Subtract 200 to both sides of inequality
644-200=200-200+12x
444=12x
Divide by 12 every side of inequality.
444/12=12x/12
37=x