Verified Answer :

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

=a - 2b + 3c -a + 2b + 3c - d

=6c -d

Answer:  The required value is \(6c-d.\)

Step-by-step explanation:  We are given to find the following :

\(a-2b+3c\) diminished by \(a-2b-3c+d.\)

We know that

the expression p diminished by q is written as "p - q".

Therefore, the given expression implies

\(a-2b+3c~\textup{diminished by}~a-2b-3c+d\\\\=(a-2b+3c)-(a-2b-3c+d)\\\\=a-2b+3c-a+2b+3c-d\\\\=6c-d.\)

Thus, the required value is \(6c-d.\)