Deshawn has several dimes and quarters that total $2.05. he has 3 fewer quarters than dimes. how many of each doe he have

Let
x = the number of dimes
y = the number of quarters

The total sum is $2.05, therefore
0.10x + 0.25y = 2.05
Divide through by 0.05 to obtain
2x + 5y = 41                 (1)

There are 3 fewer quarters than dimes, therefore
y = x - 3                      (2)

Substitute (2) into (1).
2x + 5(x - 3) = 41
2x + 5x - 15 = 41
7x = 56
x = 8
y = x - 3 = 5

8 dimes, 5 quarters