Use the Quadratic Formula to Solve the Equation $$\mathrm { y } ^ { 2 } - 18 \mathrm { y } + 81 = 0$$

Multiple Choice

Use the quadratic formula to solve the equation.
- $$\mathrm { y } ^ { 2 } - 18 \mathrm { y } + 81 = 0$$

A) $\{ - 9,9 \}$
B) $\{ - 9 - i , - 9 + i \}$
C) $\{ - 9 \}$
D) $\{ 9 \}$