Center city east parking garage has a capacity of 257 cars more than center city west parking garage. if the combined capacity for the two garages is 1221 cars, find the capacity for each garage.

Center City West = x
Center City East = (x + 257)

Solve for x to find the capacity for Center City West and then we can find the capacity for Center City East.

(x + 257) + x = 1221
x + x + 257 = 1221
2x  + 257 - 257 = 1221 - 257
2x = 964
2x / 2 = 964 / 2
x = 482
Center City West capacity = 482

Now to find Center City East capacity we substitute 482 for x in (x + 257) 

(x + 257) 
(482 + 257)
482 + 257 = 739

Center City East capacity  = 739
Center City West capacity = 482