$\"Subtraction$

$\"\"$

The equation is $\"\"$ .

$\"\"$ (Subtract 20 from each side)

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

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

$\"\"$

Check:

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

$\"\"$

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

The statement is true.

$\"\"$

The value of $\"\"$ .