x = number of dimes
y = number of quarters
---
10x + 25y = 2565
y = x + 20
---
put the system of linear equations into standard form
---
10x + 25y = 2565
x - y = -20
---
copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
---
solution:
x = 59
y = 79
