Answer:
Word: x patch longer after x weeks an 3x patches wider after x weeks 
The symbol: 3+ x*1 and 5+ 3x after x weeks 
Explanation:
Given that: 
- 3 patches long 
 - 5 patches wide
 - Each week, she plans to make the quilt 1 patch longer and 3 patches wider 
 
For example, we will have a table of values: 
Week Length Width 
1 3 5 
2 3+1 5+3 
3 3+1+1 5+3 +3 
…. ..... ......... 
x 3+ x*1 5+ 3x 
Word: x patch longer after x weeks an 3x patches wider after x weeks 
The symbol: 3+ x*1 and 5+ 3x after x weeks