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5 votes
Complete the square to re-write the quadratic function in vertex form:
y = x2 + 4x – 9

User DavAlPi
by
8.1k points

2 Answers

1 vote

Answer:

y = (x + 2)² - 13

Explanation:

y = x² + 4x - 9

To complete the square

add/ subtract ( half the coefficient of the x- term)² to x² + 4x

y = x² + 2(2)x + 4 - 4 - 9

= (x + 2)² - 13 ← in vertex form

User Magma
by
7.6k points
0 votes

Answer: − 2 ± √ 13

Explanation:

(-b±√(b²-4ac))/(2a)

Plug in and solve.

User Vanlandingham
by
9.5k points

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