Q. Complete the square to re-write the quadratic function in vertex form:y=x2+8x−9Answer: y=
Identify Vertex Form: Identify the vertex form of a parabola. The vertex form of a parabola is given by y=a(x−h)2+k, where (h,k) is the vertex of the parabola.
Begin with Quadratic Function: Begin with the given quadratic function.We have the quadratic function y=x2+8x−9.
Separate Constant Term: Separate the constant term from the x terms.To complete the square, we need to isolate the x terms. So we write the function as y=(x2+8x)−9.
Find Completing Number: Find the number to complete the square.To complete the square, we need to add and subtract the square of half the coefficient of x inside the parentheses. The coefficient of x is 8, so half of it is 4, and the square of 4 is 16. We will add and subtract 16 inside the parentheses.
Add/Subtract Square: Add and subtract the square of half the coefficient of x inside the parentheses.We write the function as y=(x2+8x+16)−16−9.
Factor and Simplify: Factor the perfect square trinomial and simplify the constants.The expression x2+8x+16 is a perfect square trinomial and can be factored as (x+4)2. The constants −16 and −9 combine to −25. So the function becomes y=(x+4)2−25.
Write Final Vertex Form: Write the final vertex form of the quadratic function.The vertex form of the quadratic function is y=(x+4)2−25.
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