$\"\"$

The expression is $\"\"$ .

Addition property of equality:

If x – a = b, then x – a + a = b + a, or x = b + a.

$\"\"$ (Add 7 to each side)

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

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

$\"\"$

Check:

Check the solution by substituting $\"\"$ in the original equation.

$\"\"$

$\"\"$ (Subtract: 13 – 7 = 6)

$\"\"$

The value of $\"\"$