Question

Transform the given quadratic function into vertex form f(x) = quadratic function into vertex form f(x) = quadratic function into vertex form $f(x) = (x-h)^{2} + k$ by completing the square. $a(x-h)^{2} +k$ by completing the square.
$f(x) = 3x^{2} -4x-6$

Answer 1

Answer:

$f(x) = 3(x -\frac{2}{3})^2 -\frac{22}{3}$

The vertex is $(\frac{2}{3}, -\frac{22}{3})$

Step-by-step explanation:

For a general quadratic function the form is:

$ax ^ 2 + bx + c$

For the function

$f(x) = 3x ^ 2 -4x -6$

Take common factor 3.

$f(x) = 3(x ^ 2 -\frac{4}{3}x - 2)$

The values of the coefficients for the function within the parenthesis are the following: $a = 1$, $b = -\frac{4}{3}$, $c = -2$

Take the value of b and divide it by 2. Then, the result obtained squares it.

$\frac{b}{2}= -\frac{2}{3}$

$(\frac{b}{2})^2=\frac{4}{9}$

Add and subtract $\frac{4}{9}$

$f(x) = 3([x ^ 2 -\frac{4}{3}x +\frac{4}{9}]- 2-\frac{4}{9})$

Write the expression of the form

$f(x) = (x-\frac{b}{2})^2 +k$

$f(x) = 3(x -\frac{2}{3})^2 -\frac{22}{3}$

The vertex is $(\frac{2}{3}, -\frac{22}{3})$