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30 Use the method of completing the square to determine the vertex of f(x) = x² - 14x - 15.

State the coordinates of the vertex.

User AlfredBr
by
6.9k points

1 Answer

8 votes

Answer:

x² - 14x - 15 = (x − 7)² − 64

Then the coordinates of the vertex are (7 , -64)

Explanation:

x² - 14x - 15 = x² - 14x + (49 - 49) - 15

= (x² - 14x + 49) - 49 - 15

= (x² - 14x + 7²) - 49 - 15

= (x − 7)² − (49 + 15)

= (x − 7)² − 64

x² - 14x - 15 = (x − 7)² − 64

Then the coordinates of the vertex are (7 , -64)

User Brian Ogden
by
6.6k points
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