Find the Vertex Form g(x)=2x^2-4x-5

$g (x) = 2 x^{2} - 4 x - 5$

Step 1

Write $g (x) = 2 x^{2} - 4 x - 5$ as an equation.

$y = 2 x^{2} - 4 x - 5$

Step 2

Complete the square for $2 x^{2} - 4 x - 5$ .

Use the form $a x^{2} + b x + c$ , to find the values of $a$ , $b$ , and $c$ .

$a = 2$

$b = - 4$

$c = - 5$

Consider the vertex form of a parabola.

$a {(x + d)}^{2} + e$

Find the value of $d$ using the formula $d = \frac{b}{2 a}$ .

Substitute the values of $a$ and $b$ into the formula $d = \frac{b}{2 a}$ .

$d = \frac{- 4}{2 \cdot 2}$

Simplify the right side.

Cancel the common factor of $- 4$ and $2$ .

Factor $2$ out of $- 4$ .

$d = \frac{2 \cdot - 2}{2 \cdot 2}$

Cancel the common factors.

Factor $2$ out of $2 \cdot 2$ .

$d = \frac{2 \cdot - 2}{2 (2)}$

Cancel the common factor.

$d = \frac{2 \cdot - 2}{2 \cdot 2}$

Rewrite the expression.

$d = \frac{- 2}{2}$

Cancel the common factor of $- 2$ and $2$ .

Factor $2$ out of $- 2$ .

$d = \frac{2 \cdot - 1}{2}$

Cancel the common factors.

Factor $2$ out of $2$ .

$d = \frac{2 \cdot - 1}{2 (1)}$

Cancel the common factor.

$d = \frac{2 \cdot - 1}{2 \cdot 1}$

Rewrite the expression.

$d = \frac{- 1}{1}$

Divide $- 1$ by $1$ .

$d = - 1$

Find the value of $e$ using the formula $e = c - \frac{b^{2}}{4 a}$ .

Substitute the values of $c$ , $b$ and $a$ into the formula $e = c - \frac{b^{2}}{4 a}$ .

$e = - 5 - \frac{{(- 4)}^{2}}{4 \cdot 2}$

Simplify the right side.

Simplify each term.

Cancel the common factor of ${(- 4)}^{2}$ and $4$ .

Rewrite $- 4$ as $- 1 (4)$ .

$e = - 5 - \frac{{(- 1 (4))}^{2}}{4 \cdot 2}$

Apply the product rule to $- 1 (4)$ .

$e = - 5 - \frac{{(- 1)}^{2} \cdot 4^{2}}{4 \cdot 2}$

Raise $- 1$ to the power of $2$ .

$e = - 5 - \frac{1 \cdot 4^{2}}{4 \cdot 2}$

Multiply $4^{2}$ by $1$ .

$e = - 5 - \frac{4^{2}}{4 \cdot 2}$

Factor $4$ out of $4^{2}$ .

$e = - 5 - \frac{4 \cdot 4}{4 \cdot 2}$

Cancel the common factors.

Factor $4$ out of $4 \cdot 2$ .

$e = - 5 - \frac{4 \cdot 4}{4 (2)}$

Cancel the common factor.

$e = - 5 - \frac{4 \cdot 4}{4 \cdot 2}$

Rewrite the expression.

$e = - 5 - \frac{4}{2}$

Cancel the common factor of $4$ and $2$ .

Factor $2$ out of $4$ .

$e = - 5 - \frac{2 \cdot 2}{2}$

Cancel the common factors.

Factor $2$ out of $2$ .

$e = - 5 - \frac{2 \cdot 2}{2 (1)}$

Cancel the common factor.

$e = - 5 - \frac{2 \cdot 2}{2 \cdot 1}$

Rewrite the expression.

$e = - 5 - \frac{2}{1}$

Divide $2$ by $1$ .

$e = - 5 - 1 \cdot 2$

Multiply $- 1$ by $2$ .

$e = - 5 - 2$

Subtract $2$ from $- 5$ .

$e = - 7$

Substitute the values of $a$ , $d$ , and $e$ into the vertex form $2 {(x - 1)}^{2} - 7$ .

$2 {(x - 1)}^{2} - 7$

Step 3

Set $y$ equal to the new right side.

$y = 2 {(x - 1)}^{2} - 7$

Find the Vertex Form g(x)=2x^2-4x-5

Related Questions

Support LCMGCF.com by disabling your adblocker.