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Which equation is y=9x^2+9x-1 re-written in vertex form

Which equation is y=9x^2+9x-1 re-written in vertex form-example-1

2 Answers

6 votes

Answer:

A. y = 9(x +1/2)^2 - 13/4.

Explanation:

y = 9x^2 + 9x - 1

y = 9(x^2 + x) - 1

y = 9 [ (x + 1/2)^2 - 1/4] - 1

y = 9 (x + 1/2)^2 - 9/4 - 1

y = 9(x +1/2)^2 - 13/4.

User Crosenblum
by
6.3k points
3 votes

Answer: First Option


y = (x+(1)/(2)) ^ 2 -(13)/(4)[

Explanation:

For a quadratic function of the form:


y = ax ^ 2 + bx + c

The vertex form of the equation is:


y = (x-h) ^ 2 + k

Where the vertex is the point (h, k) and
h =-(b)/(2a)

In this case the equation is:
y=9x^2+9x-1

So:


a=9\\b=9\\c=-1

Therefore:


h =-(9)/(2*(9))


h =-(1)/(2)


k=9(-(1)/(2))^2+9(-(1)/(2))-1\\\\k=-(13)/(4)

Finally the equation in vertex form is:


y = (x+(1)/(2)) ^ 2 -(13)/(4)[

User Rudivonstaden
by
7.0k points