Solve the equation $x ^ { 2 } - 12 x - 45 = 0$ by completing the square.

Question

Quizplus · Accepted Answer

To solve the equation $x^2 - 12x - 45 = 0$ by completing the square, we first move the constant term to the other side: $x^2 - 12x = 45$. Then, we add $\left(\frac{12}{2}\right)^2 = 36$ to both sides to complete the square: $x^2 - 12x + 36 = 81$. This gives us $(x - 6)^2 = 81$, so $x - 6 = \pm9$. Solving for $x$, we get $x = 6 + 9 = 15$ and $x = 6 - 9 = -3$.

Solve the Equation x2−12x−45=0x ^ { 2 } - 12 x - 45 = 0x2−12x−45=0

Solve the Equation $x ^ { 2 } - 12 x - 45 = 0$