Before: March 15, 2018 Tell whether the graph of each quadratic function opens upward or downward. Explain. y = 7x² - 4x x – 3x² + y = 5 y = -2/3x²

During: Characteristics of Quadratic Functions

Recall that an x-intercept of a function is a value of x when y = 0. A zero of a function is an x-value that makes the function equal to 0. So a zero of a function is the same as an x-intercept of a function. Since a graph intersects the x-axis at the point or points containing an x-intercept these intersections are also at the zeros of the function. A quadratic function may have one, two, or no zeros.

“We Do” Finding Zeros of Quadratic Functions From Graphs Find the zeros of each quadratic function from its graph. Check your answer.

“We Do” Finding Zeros of Quadratic Functions From Graphs Find the zeros of each quadratic function from its graph. Check your answer.

“We Do” Finding Zeros of Quadratic Functions From Graphs Find the zeros of each quadratic function from its graph. Check your answer.

“You Do” Finding Zeros of Quadratic Functions From Graphs Find the zeros of each quadratic function from its graph. Check your answer.

“You Do” Finding Zeros of Quadratic Functions From Graphs Find the zeros of each quadratic function from its graph. Check your answer.

A vertical line that divides a parabola into two symmetrical halves is the axis of symmetry. The axis of symmetry always passes through the vertex of the parabola. You can use the zeros to find the axis of symmetry.

“We Do” Finding the Axis of Symmetry by Using Zeros Find the axis of symmetry of each parabola.

“We Do” Finding the Axis of Symmetry by Using Zeros Find the axis of symmetry of each parabola.

“You Do” Finding the Axis of Symmetry by Using Zeros Find the axis of symmetry of each parabola.

“You Do” Finding the Axis of Symmetry by Using Zeros Find the axis of symmetry of each parabola.

Finding the Axis of Symmetry by Using the Formula Example For a quadratic function y = ax² + bx + c, the axis of symmetry is the vertical line: x = -b 2a y = 2x² + 4x + 5

“I Do” Finding the Axis of Symmetry by Using the Formula Find the axis of symmetry of the graph of y = x² + 3x + 4.

“We Do” Finding the Axis of Symmetry by Using the Formula Find the axis of symmetry of the graph of y = 2x² + x + 3.

“You Do” Finding the Axis of Symmetry by Using the Formula Find the axis of symmetry of the graph of y = -3x² + 10x + 9.

Finding the Vertex of a Parabola Once you have found the axis of symmetry, you can use it to identify the vertex. Finding the Vertex of a Parabola Step 1: To find the x-coordinate of the vertex, find the axis of symmetry by using zeros or the formula. Step 2: To find the corresponding y-coordinate, substitute the x-coordinate of the vertex into the function. Step 3: Write the vertex as an ordered pair.

“We Do” Finding the Vertex of a Parabola Find the vertex. y = -3x² + 6x - 7

“You Do” Finding the Vertex of a Parabola Find the vertex. y = x² - 4x - 10

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