Questions: Question
Rewrite the following quadratic function in standard (vertex) form.
f(x)=-7x^2-4x-6
Enter exact values and use improper fractions, if necessary.
Provide your answer below:
f(x)=
Transcript text: Question
Rewrite the following quadratic function in standard (vertex) form.
\[
f(x)=-7 x^{2}-4 x-6
\]
Enter exact values and use improper fractions, if necessary.
Provide your answer below:
\[
f(x)=
\]
$\square$
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Solution
Solution Steps
To rewrite the quadratic function in standard (vertex) form, we need to complete the square. This involves rearranging the quadratic expression into a perfect square trinomial plus a constant. The standard form of a quadratic function is \( f(x) = a(x-h)^2 + k \), where \((h, k)\) is the vertex of the parabola.
To rewrite the quadratic function in standard (vertex) form, we will complete the square.
Step 1: Identify the Coefficients
The given quadratic function is:
\[
f(x) = -7x^2 - 4x - 6
\]
Here, the coefficients are \(a = -7\), \(b = -4\), and \(c = -6\).
Step 2: Factor Out the Leading Coefficient
First, factor out the leading coefficient \(-7\) from the terms involving \(x\):
\[
f(x) = -7(x^2 + \frac{4}{7}x) - 6
\]
Step 3: Complete the Square
To complete the square, take the coefficient of \(x\) inside the parentheses, \(\frac{4}{7}\), divide it by 2, and square it:
\[
\left(\frac{4}{7} \times \frac{1}{2}\right)^2 = \left(\frac{2}{7}\right)^2 = \frac{4}{49}
\]
Add and subtract this square inside the parentheses:
\[
f(x) = -7\left(x^2 + \frac{4}{7}x + \frac{4}{49} - \frac{4}{49}\right) - 6
\]
Step 4: Simplify the Expression
Rewrite the expression by completing the square:
\[
f(x) = -7\left((x + \frac{2}{7})^2 - \frac{4}{49}\right) - 6
\]
Distribute the \(-7\) and simplify:
\[
f(x) = -7(x + \frac{2}{7})^2 + \frac{28}{49} - 6
\]
Convert \(\frac{28}{49}\) to a simpler form:
\[
\frac{28}{49} = \frac{4}{7}
\]
Thus, the function becomes:
\[
f(x) = -7(x + \frac{2}{7})^2 + \frac{4}{7} - 6
\]