Find the zeros of y=x2-4x-9 by completing the square
1 answer:
Answer:
x = 2 ±
Step-by-step explanation:
To find the zeros let y = 0, that is
x² - 4x - 9 = 0 ( add 9 to both sides )
x² - 4x = 9
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 2) x + 4 = 9 + 4
(x - 2)² = 13 ← take the square root of both sides
x - 2 = ± ← add 2 to both sides
x = 2 ±
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Answer:
Step-by-step explanation:
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In other words, we want to find a polynomial function with roots x=3 , multiplicity, 3.
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We expand to get:
This simplifies to:
See attachment for graph.
