$\"\"$

The expression is $\"\"$ .

The square of a difference formula: $\"\"$ .

The expression $\"\"$ is comparison with $\"\"$ .

So $\"\"$ .

Consider $\"\"$ . $\"\"$

The value of $\"\"$ substitute in the $\"\"$ .

$\"\"$

Divide each side by negative 10x.

$\"\"$

$\"\"$ .

The value of $\"\"$ substitute in the $\"\"$ . $\"\"$

The value of $\"\"$ .