Question

what is f(x) = 2x2 28x – 5 written in vertex form? f(x) = 2(x 7)2 – 19 f(x) = 2(x 7)2 – 103 f(x) = 2(x 14)2 – 14 f(x) = 2(x 14)2 – 98

Answer 1

Hello,
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Answer B
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2x²+28x-5=2(x²+2*7x+49)-5-2*48
=2(x+7)²-103

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Answer 2

`f(x)=2(x+7)^2-103`

Explanation:

`f(x) = 2x^2+28x - 5`

To find out vertex apply the formula x=-b/2a

The value of a=2 and b=28

`x=(-b)/(2a) =(-28)/(4) =-7`

Now plug in x=-7 in f(x) equation and find out f(-7)

`f(-7) = 2(-7)^2+28(-7)- 5=-103`

Vertex is (-7,-103)

Now use vertex formula

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

a=2, h=-7, k=-103

Plug in all the values in the vertex form equation

`f(x)=2(x+7)^2-103`