$\"\"$

The equation is $\"\"$ .

Subtract 36x from each side.

$\"\"$

Compare the equation with $\"\"$ .

a = 4, b = $\"\"$ and c = 81.

Apply quadratic formula: $\"\"$ .

$\"\"$ (Replace a with 4, b with $\"\"$ , and c with 81)

Product of two same sings is positive.

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

$\"\"$

The solution is $\"\"$ .