Question
What is the intermediate step in the form \( (x+a)^{2}=b \) as a result of completing the square for the following equation? \[ 4 x^{2}-72 x=-68 \]
Ask by Ryan Ingram. in the United States
Jan 27,2025
Real Tutor Solution
Tutor-Verified Answer
Answer
After completing the square, an intermediate step is \( (x - 9)^2 = 64 \).
Solution
To complete the square for the equation
\[
4x^{2} - 72x = -68,
\]
follow these steps:
1. **Divide by 4** to make the coefficient of \(x^2\) equal to 1:
\[
x^{2} - 18x = -17.
\]
2. **Complete the square** on the left side. Take half of the coefficient of \(x\) (which is \(-18\)), square it, and add it to both sides:
\[
x^{2} - 18x + \left(\frac{-18}{2}\right)^2 = -17 + \left(\frac{-18}{2}\right)^2.
\]
\[
x^{2} - 18x + 81 = 64.
\]
3. **Rewrite the left side** as a perfect square:
\[
(x - 9)^2 = 64.
\]
The **intermediate step** in the form \( (x + a)^2 = b \) is:
\[
(x - 9)^2 = 64.
\]
**Answer:** After completing the square, an intermediate step is ( x – 9 ) squared equals 64, that is
(x−9)² = 64
Reviewed and approved by the UpStudy tutoring team
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The Deep Dive
To complete the square for the equation \( 4x^2 - 72x = -68 \), we first divide all terms by 4 to simplify it to \( x^2 - 18x = -17 \). The next step involves finding the number to complete the square. We take half of the coefficient of \( x \) (which is \(-18\)), square it, giving us \( (-9)^2 = 81 \). Now we rewrite the equation as \( (x - 9)^2 = -17 + 81 \), leading us to \( (x - 9)^2 = 64 \). This gives us a clean completed square equation to work with!