# Vertex & axis of Symmetry I can calculate vertex and axis of symmetry from an equation.

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Vertex & axis of Symmetry I can calculate vertex and axis of symmetry from an equation.

Roots, Vertex & axis of Symmetry Quadratic Function: y = x 2 Graph: Parabola Roots/x-intercepts (Where the function crosses the x-axis.) x value(s) when y = 0 ( ___, 0) y-intercept: Where the function crosses the y-axis. y value when x = 0 ( 0, ___ ) axis of symmetry: Vertical line through the vertex. x = x-coordinate of vertex Vertex: The high or low point of graph; where the graph changes direction. {ordered pair in the form of (x,y)}

Vertex & axis of symmetry from an equation Quadratic Function General Form: y = ax 2 + bx + c 23-8 y = 3x – 8x 2 + 2 -170-3 y = -3x 2 – 17 6-51 y = x 2 – 5x + 6 1224 y = 4x 2 + 2x + 12 732 y = 2x 2 + 3x + 7 cba Equation

Axis of symmetry: y = 2x 2 + 8x + 17 a = 2 b = 8 y = ax 2 + bx + c y = 2x 2 – 20x + 54 a = 2 b = -20 y = -3x 2 + 6x + 3 a = -3 b = 6 y = x 2 + 12x + 85 a = 1 b = 12 x = -2 x = 5 x = 1 x = 6

Vertex: the high or low point of the graph (x, y) The x value is the axis of symmetry so: y = x 2 + 6x + 5 a = 1 b = 6 y = x 2 + 6x + 5 y = (-3) 2 + 6(-3) + 5 y = 9 + (-18) + 5 y = -4 x = -3 (-3, -4) Axis of symmetry Vertex

Vertex: the high or low point of the graph (x, y) The x value is the axis of symmetry so: y = 3x 2 + 6x – 18 a = 3 b = 6 y = 3x 2 + 6x – 18 y = 3(-1) 2 + 6(-1) – 18 y = 3(1) + 6(-1) – 18 y = 3 + (-6) – 18 y = -21 x = -1 (-1, -21) Axis of symmetry Vertex Pg 556: 7-15, 37-39

I can calculate vertex and line of symmetry from an equation. Assignment: Pg 550: 16-19; Pg 556: 7-16, 37-39

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