$\"\"$

The expression is $\"\"$ .

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

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

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

$\"\"$ (The quotient of two same signs is positive)

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

The solution is $\"\"$ .