$\"\"$ $\"\"$

The expression is $\"\"$

According to subtraction property of equality: If a = b then a - c = b - c

$\"\"$ (Subtract $\"\"$ from each side)

$\"\"$ (Additive inverse property: $\"\"$ )

$\"\"$ (Additive identity property: $\"\"$ ) $\"\"$

The value of $\"\"$ .