1. The cost of a notebook is \(₹7\) less than thrice the cost of a pen.
The equation is .
2. The difference between the cost of \(5\) pencils and \(6\) erasers is \(₹ 9\).
The equation is .
[Note: Here we have considered one of the variable as '\(x\)' and the other variable as '\(y\)']