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

The expression is $\"\"$ .

According to addition property of equality: Add 0.4 to each side.

$\"\"$ (Add 0.4 from each side)

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

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

Check:

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

$\"\"$

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

The value of $\"\"$ .