How do you identify the important parts of y=7x2 to graph it?

1 Answer
Oct 9, 2015

The axis of symmetry is x=0/
The vertex is (0,0).

Explanation:

y=7x2 is a quadratic equation in standard form ax2+bx+c, where a=7,b=0,andc=0.

Axis of Symmetry: an imaginary vertical line the divides the parabola into two equal halves.

Formula for axis of symmetry: x=b2a

Since b=0, the axis of symmetry is x=0.

Vertex: The maximum or minimum point (x,y) of a parabola. Since the coefficient of a is negative, this parabola opens downward and the vertex is the maximum point. The x value for the vertex is the value for the axis of symmetry, where x=0.

To find the y value of the vertex, we substitute 0 for x in the equation and solve for y.

y=7x2=

y=7(0)2=0

The vertex is (0,0).

Determine a few points on both sides of the axis of symmetry.

x=2, y=28
x=1, y=7
x=0, y=0 (vertex)
x=1, y=7
x=2, y=28

Plot the points and sketch a curved parabola through the points. Do not connect the dots.

graph{y=-7x^2 [-14.49, 17.53, -11.08, 4.94]}