Maths-
General
Easy
Question
Find the axis of symmetry, vertex and y-intercept of the function
f(x) = 2x2 + 8x + 2
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: 2
This quadratic function is in standard form, f(x)=ax2+bx+c.
For every quadratic function in standard form the axis of symmetry is given by the formula x=−b/2a.
In f(x)= 2x2 + 8x + 2, a= 2, b= 8, and c= 2. 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)= 2x2 + 8x + 2 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 = 2(h)2 + 8(h) + 2
k = 2(-2)2 + 8(-2) + 2
k = 8 – 16 + 2
k = -6
Therefore, the vertex is (-2 , -6)
For finding the y- intercept we firstly rewrite the equation by substituting 0 for x.
y = 2(0)2 + 8(0) + 2
y = 0 + 0 + 2
y = 2
Therefore, Axis of symmetry is x = -2
Vertex is ( -2 , -6)
Y- intercept is 2.
The equation of the axis of symmetry for f(x)= 2x2 + 8x + 2 is x = -2.
The x coordinate of the vertex is the same:
The y coordinate of the vertex is :
Therefore, the vertex is (-2 , -6)
For finding the y- intercept we firstly rewrite the equation by substituting 0 for x.
Therefore, Axis of symmetry is x = -2
Vertex is ( -2 , -6)
Y- intercept is 2.
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