Let the absolute value equation be this:

|x + a| = b  (where b is a non-negative number)

Then the two equations resulting from this are:

x + a = b,    x + a = -b

Let's substitute 20320 for x in the first equation
and -282 in the second equation:

20320 + a = b    -282 + a = b

So we have this system of euations:



or we can write it better this way:



Can you solve that system, either by substitution
or elimination?  If not post again
asking how.

Solution:  a = - 10019,  b = 10301

So the equation

|x + a| = b

becomes:

|x - 10019| = 10301  

Edwin