Objective Writing a Quadratic Function in Vertex Form
Objective: Writing a Quadratic Function in Vertex Form Write the function in vertex form, and identify its vertex. f(x) = x 2 + 16 x – 12 f(x)=(x 2 + 16 x + ) – 12 – Set up to complete the square. Add and subtract Simplify and factor. Because h = and k = , the vertex is ( ). .
Example 4 A Continued Check Use the axis of symmetry formula to confirm vertex. y = f(– 8) = (– 8)2 + 16(– 8) – 12 = – 76
Write the function in vertex form, and identify its vertex g(x) = 3 x 2 – 18 x + 7
Because h = and k = , the vertex is ( Check A graph of the function on a graphing calculator supports your answer. ).
Write the function in vertex form, and identify its vertex f(x) = x 2 + 24 x + 145 Set up to complete the square. Add and subtract Simplify and factor. Because h = and k = , the vertex is ( ). .
Write the function in vertex form, and identify its vertex g(x) = 5 x 2 – 50 x + 128
Because h = and k = , the vertex is ( , ). Check A graph of the function on a graphing calculator supports your answer.
Lesson Quiz 1. Complete the square for the expression x 2 – 15 x +. Write the resulting expression as a binomial squared. Solve each equation. 2. x 2 – 16 x + 64 = 20 3. x 2 – 27 = 4 x Write each function in vertex form and identify its vertex. 5. f(x) = 2 x 2 – 12 x – 27 4. f(x)= x 2 + 6 x – 7
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