$\"\"$

The equation is $\"\"$ .

Apply subtraction property of equality: Subtract 9 from each side. \ \

$\"\"$

Apply commutative property of addition: $\"\"$ .

$\"\"$

$\"\"$ (Apply additive inverse property: $\"\"$ )

$\"\"$ (Apply additive identity property: $\"\"$ )

$\"\"$ (Subtract: $\"\"$ ) $\"\"$

Check:

To check the solution, substitute $\"\"$ in original equation $\"\"$ .

$\"\"$ (Substitute $\"\"$ )

$\"\"$ (Subtract: $\"\"$ )

The solution is true. $\"\"$

The value of p is $\"\"$ .