Complete the square to solve the following quadratic equation: x^2−22x+1=15

.(1 point)
Responses

x=11+14−−√, 11−14−−√
x equals 11 plus Start Root 14 End Root comma 11 minus Start Root 14 End Root

x=−11+315−−√, −11−315−−√
x equals negative 11 plus 3 Start Root 15 End Root comma negative 11 minus 3 Start Root 15 End Root

x=11+315−−√, 11−315−−√
x equals 11 plus 3 Start Root 15 End Root comma 11 minus 3 Start Root 15 End Root

x=−11+14−−√, −11−14−−√

1 answer

To solve the quadratic equation \(x^2 - 22x + 1 = 15\) by completing the square, we first rewrite the equation in standard form:

\[ x^2 - 22x + 1 - 15 = 0 \]

This simplifies to:

\[ x^2 - 22x - 14 = 0 \]

Next, we move the constant to the right side:

\[ x^2 - 22x = 14 \]

Now, to complete the square, we take the coefficient of \(x\), which is \(-22\), divide by 2, and square it:

\[ \left(-\frac{22}{2}\right)^2 = (-11)^2 = 121 \]

We add this square on both sides:

\[ x^2 - 22x + 121 = 14 + 121 \]

This simplifies to:

\[ (x - 11)^2 = 135 \]

Next, we take the square root of both sides:

\[ x - 11 = \pm \sqrt{135} \]

Thus, we solve for \(x\):

\[ x = 11 \pm \sqrt{135} \]

We can simplify \(\sqrt{135}\):

\[ \sqrt{135} = \sqrt{9 \times 15} = 3\sqrt{15} \]

So the solutions for \(x\) are:

\[ x = 11 + 3\sqrt{15} \quad \text{and} \quad x = 11 - 3\sqrt{15} \]

Hence, the correct response is:

x equals \(11 + 3\sqrt{15}, 11 - 3\sqrt{15}\).