Maths-

General

Easy

Question

# Graph f(x) = 2x^{2} + 8x - 1. What are axis of symmetry, vertex and y-intercept of the function

Hint:

### For a quadratic function is in standard form, f(x)=ax2+bx+c.

A vertical line passing through the vertex is called the axis of symmetry for the parabola.

Axis of symmetry x=−b/2a

Vertex The vertex of the parabola is located at a pair of coordinates which we will call (*h, k*). where h is value of x in axis of symmetry formula and k is f(h).

The *y*-intercept is the point where a graph crosses the *y*-axis. In other words, it is the value of *y* when x=0.

## The correct answer is: -1

This quadratic function is in standard form, f(x)=ax^{2}+bx+c.

For every quadratic function in standard form the axis of symmetry is given by the formula x=−b/2a.

In f(x)=2x^{2}+8x-1, a=2, b=8, and c=-1. So, the equation for the axis of symmetry is given by

x = −(8)/2(2)

x = - 8/4

x = -2

The equation of the axis of symmetry for f(x)=2x^{2}+8x-1 is x = -2.

The x coordinate of the vertex is the same:

h = -2

The y coordinate of the vertex is :

k = f(h)

k = (h)^{2} + 8(h) - 1

k = 2(-2)^{2} + 8(-2) - 1

k = 8 – 16 - 1

k = -9

Therefore, the vertex is (-2 , -9)

For finding the y- intercept we firstly rewrite the equation by substituting 0 for x.

y = 2(0)^{2} + 8(0) - 1

y = 0 + 0 - 1

y = -1

Therefore, Axis of symmetry is x = -1

Vertex is ( -2 , -9 )

Y- intercept is -1.

### Related Questions to study

Maths-

### Graph f(x) = -0.75x^{2} + 3x - 4. What are axis of symmetry, vertex and y-intercept of the function

### Graph f(x) = -0.75x^{2} + 3x - 4. What are axis of symmetry, vertex and y-intercept of the function

Maths-General

Maths-

### Graph f(x) = x^{2} + 2x + 4. What are axis of symmetry, vertex and y-intercept of the function

### Graph f(x) = x^{2} + 2x + 4. What are axis of symmetry, vertex and y-intercept of the function

Maths-General

Maths-

### Graph f(x) = 2x^{2} + 4x + 3. What are axis of symmetry, vertex and y-intercept of the function

### Graph f(x) = 2x^{2} + 4x + 3. What are axis of symmetry, vertex and y-intercept of the function

Maths-General

Maths-

### Evaluate f(x) = ax^{2} + bx + c for x = 0. How does f(0) relate to the result in the above question?

### Evaluate f(x) = ax^{2} + bx + c for x = 0. How does f(0) relate to the result in the above question?

Maths-General

Maths-

### What information does c provide above the graph of f(x) = ax^{2} + bx + c

### What information does c provide above the graph of f(x) = ax^{2} + bx + c

Maths-General

Maths-

### In a survey, customer select item A or item B. Item A is selected by 20 males 10 females. Of 20 customers who select item B, five are males.

Construct a two-way frequency table to organize the data.

### In a survey, customer select item A or item B. Item A is selected by 20 males 10 females. Of 20 customers who select item B, five are males.

Construct a two-way frequency table to organize the data.

Maths-General

General

### Which verb is the action verb ?

She is walking on footpath .

### Which verb is the action verb ?

She is walking on footpath .

GeneralGeneral

Maths-

### Complete the two-way table:

### Complete the two-way table:

Maths-General

Maths-