Answer:
Givens
- The pair of shoes cost $58.
 - He saved $32.
 - He still need to save 
 dollars to buy them. 
Basically, if you analyse the problem, you'll deduct that the sum between his saving and the dollars missing, that must be equalt to the cost of the pair of shoes. All this can be expressed as

Which we can solve for 


Now, if we need to express the situation generally, it would be

Where 
 refers to savings, 
 refers to dollars missing and 
 refers to the cost of the pair of shoes.