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25 votes
25 votes
Determine the vertex by completing the square. Show process.

y = x2 -6x + 28
Help please

User Ben Jaspers
by
2.5k points

1 Answer

28 votes
28 votes

Answer:

vertex = (3, 19 )

Explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k ) are the coordinates of the vertex and a is a multiplier

Using the method of completing the square

add/subtract ( half the coefficient of the x- term )² to x² - 6x

y = x² + 2(- 3)x + 9 - 9 + 28

= (x - 3)² - 9 + 28

= (x - 3)² + 19 ← in vertex form

vertex = (3, 19 )

User William Gunawan
by
2.7k points