Answer:
 
The equation for the number of dollars, d, you spend on b boxes is: 
 
 d = 6b 
 
Explanation: 
 
You buy boxes of strawberries at the market. 
 
Each box cost $6. 
 
Write an equation for the number of dollars, d, you spend on b boxes. 
 
Cost of 1 box = $6 
 
Cost of b boxes = $6b 
 
Dollars spent = d=6b 
 
Hence, the equation for the number of dollars, d, you spend on b boxes is: 
 
d = 6b