ALGEBRA I - SECTION 9-2 (Quadratic Functions) 12/3/2018 ALGEBRA I @ SECTION 9-2 : QUADRATIC FUNCTIONS

Questions whose answers you should know. Given the quadratic equation y = ax2 + bx + c …. 1) How does “a” effect the graph? a > 0 graph opens up larger “a” is, the narrower the graph (stretched) a < 0 graph opens down smaller “a” is, the broader the graph (compressed) 2) How does “c” effect the graph? + c shifts the graph up “c” units - c shifts the graph down “c” units

On to that thing called the internet : 3) How does “b” effect the graph? Hint : Look at the bottom of page 553 of your book for the answer. On to that thing called the internet : https://www.desmos.com/calculator

y = x2 + 3x y = x2 – 3x y = -x2 – 2 y = -x2 + 2 ANSWERS : 3 – D 5 - C Match each function with its graph. A C B D y = x2 + 3x y = x2 – 3x y = -x2 – 2 y = -x2 + 2 ANSWERS : 3 – D 5 - C 4 – A 6 - B

Find the coordinates of the vertex and the equation of the axis of symmetry for each equation. 7) y = 2x2 – 8x 8) y = -3x2 + 6x - 1 Vertex : (2, -8) Axis of Symmetry : x = 2 Vertex : (1, 2) Axis of Symmetry : x = 1

y = -2x2 + 8x - 4 vertex : AOS : (2, 4) x = 2 9) Graph the function. Label the vertex and axis of symmetry. y = -2x2 + 8x - 4 vertex : AOS : (2, 4) x = 2