$\"\"$

The expression is $\"\"$ .

$\"\"$ (Substitute a = – 3, b = 8 and c = – 12)

Additive inverse of – 8 is 8. To subtract 3, add – 8.

$\"\"$

$\"\"$ (Add: $\"\"$ ) $\"\"$

Additive inverse of – 12 is 12. To subtract – 12, add 12.

$\"\"$

$\"\"$ (Add: $\"\"$ ) $\"\"$

The simplified expression is 1.