If b-a = c-b = d-c, what expression is equal to d-b?

c - a

Step-by-step explanation:

Given that b-a = c-b = d-c, to find the expression equal to d-b, separate the equations in the manner below

b-a = d-c

and

c-b = d-c

From the first equation, subtract b from both sides such that

b - a - b = d - c - b

-a = d-c - b

Add c to both sides such that

c - a = d-c - b + c

c - a = d - b

Hence d - b is equal to c - a