$\"\"$

The expression is $\"\"$ .

$\"\"$ write $\"\"$

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

$\"\"$ (Product of two same signs is positive)

$\"\"$ (Product of two different signs is negative)

$\"\"$ (Multiply: $\"\"$ )

$\"\"$ (The quotient of two different signs is negative)

$\"\"$ (Multiply: $\"\"$ ) \ \

$\"\"$ (Divide: $\"\"$ ) $\"\"$

The solution is $\"\"$ .