Subtract:

3a - 5b + c + 2d from 7a - 3b + c - 2d

7a - 3b + c - 2d - (3a - 5b + c + 2d)

= 7a - 3b + c - 2d - 3a + 5b - c - 2d

Arrange the polynomial with like terms together and combine them.

= (7a - 3a) + (- 3b + 5b) + (c - c) + (- 2d - 2d)

= 4a + 2b - 4d

Hence, 7a - 3b + c - 2d - (3a - 5b + c + 2d) = 4a + 2b - 4d.