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Use the information provided to write the equation of the parabola in vertex form.

y=-3x2 - 6x +1
A D=3(x+3)²+2
B. y = 3(x+1)+4
y=-3(x+3)² +2
D. y=-3(x+1)+4
Please help

1 Answer

5 votes

Answer:
y=-3(x+1)^2+4

Explanation:

The vertex form of the equation of a parabola is:


f(x) = a(x - h)^2 + k

Where (h, k) is the vertex of the parabola.

To write
y=-3x^2 - 6x +1 in vertex form, you need to complete the square:

1. Move the 1 to the other side of the equation:


y-1=-3x^2 - 6x

2. Since the leading coefficient must be 1, you need to factor out -3:


y-1=-3(x^2 + 2x)

3. Divide the coefficient of the x-term inside the parentheses by 2 and square it:


((2)/(2))^2=1

4. Now add 1 inside the parethenses and -3(1) to the other side of the equation (because you factored out -3):


y-1-3(1)=-3(x^2 + 2x+1)


y-4=-3(x^2 + 2x+1)

5. Convert the right side of the equation to a squared expression:


y-4=-3(x+1)^2

6. And finally, you must solve for "y":


y=-3(x+1)^2+4

User Harsh Gundecha
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