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

\

The expression is $\"\"$

\

According to subtraction property of equality: if $\"\"$ then $\"\"$ .

\

$\"\"$ (Subtract 12 from each side)

\

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

\

$\"\"$ (Apply Additive identity property: $\"\"$ ) $\"\"$ $\"\"$ (Divide each side by 2)

\

$\"\"$ (Cancel common terms)

\

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

\

$\"\"$ (Take square root each side) $\"\"$ $\"\"$

\

Product property of square roots:

\

For nonnegative real numbers a and b, $\"\"$

\

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

\

Rewrite the ( $\"\"$ ) using imaginary unit; that is $\"\"$ where $\"\"$ .

\

$\"\"$

\

$\"\"$ (Find the square root: $\"\"$ )

\

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

\

The value of $\"\"$ .