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Warm Up For each quadratic function, find the axis of symmetry and vertex, and state whether the function opens upward o

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## Warm Up For each quadratic function, find the axis of symmetry and vertex, and state whether the function opens upward o

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**Warm Up**For each quadratic function, find the axis of symmetry and vertex, and state whether the function opens upward or downward. 1. y = x2 + 3 2. y = 2x2 3. y = –0.5x2 – 4 x = 0; (0, 3); opens upward x = 0; (0, 0); opens upward x = 0; (0, –4); opens downward**Objective**Graph and transform quadratic functions.**Remember!**You saw in Lesson 5-9 that the graphs of all linear functions are transformations of the linear parent function y = x.**The axis of symmetry is x = 0, or the y-axis.**• The vertex is (0, 0) • The function has only one zero, 0. The quadratic parent function is f(x) = x2. The graph of all other quadratic functions are transformations of the graph of f(x) = x2. For the parent function f(x) = x2:**The value of a in a quadratic function determines not only**the direction a parabola opens, but also the width of the parabola.**f(x) = 3x2**g(x) = 0.5x2 Order the functions from narrowest graph to widest. f(x) = 3x2, g(x) = 0.5x2 Find |A| for each function. The function with the narrowest graph has the greatest |A|. |3| = 3 |0.05| = 0.05**g(x) = x2**Order the functions from narrowest graph to widest. f(x) = x2, g(x) = x2,h(x) = –2x2 |1| = 1 |–2| = 2 h(x) = –2x2 The function with the narrowest graph has the greatest |A|. f(x) = x2**f(x) = –x2, g(x) = x2**g(x) = x2 Order the functions from narrowest graph to widest. The function with the narrowest graph has the greatest |A|. |–1| = 1 f(x) = –x2**The value of c makes these graphs look different. The value**of c in a quadratic function determines not only the value of the y-intercept but also a vertical translation of the graph of f(x) = ax2 up or down the y-axis.**Helpful Hint**When comparing graphs, it is helpful to draw them on the same coordinate plane.**g(x) = x2 + 3**• The graph of g(x) = x2 + 3 is wider than the graph of f(x) = x2. • The graph of g(x) = x2 + 3 opens downward. Compare the graph of the function with the graph of f(x) = x2.**Compare the graph of the function with the graph of f(x) =**x2 g(x) = 3x2**Compare the graph of each the graph of f(x) = x2.**g(x) = –x2 – 4**Compare the graph of the function with the graph of f(x) =**x2. g(x) = 3x2 + 9**Compare the graph of the function with the graph of f(x) =**x2. g(x) = x2 + 2**The quadratic function h(t) = –16t2 + c can be used to**approximate the height h in feet above the ground of a falling object t seconds after it is dropped from a height of c feet. This model is used only to approximate the height of falling objects because it does not account for air resistance, wind, and other real-world factors.**Two identical softballs are dropped. The first is dropped**from a height of 400 feet and the second is dropped from a height of 324 feet. a. Write the two height functions and compare their graphs. h1(t) = –16t2 + 400 Dropped from 400 feet. h2(t) = –16t2 + 324 Dropped from 324 feet.**The graph of h2 is a vertical translation of the graph of**h1. Since the softball in h1 is dropped from 76 feet higher than the one in h2, the y-intercept of h1 is 76 units higher. b. Use the graphs to tell when each softball reaches the ground.**Caution!**Remember that the graphs show here represent the height of the objects over time, not the paths of the objects.