What is the vertex form of y= 8x^2+3x-2 y=8x2+3x2?

1 Answer
Oct 5, 2016

Vertex (-3/16,-73/32)(316,7332)

Explanation:

We will need to complete the square to solve this equation.

First move the constant to the other side of the equation by adding 22 to both sides.

8x^2+3x=28x2+3x=2

Factor out the coefficient, 88, from the x^2 term.

8(x^2+3/8x)=28(x2+38x)=2

Take the coefficient of the xx term and divide it by 2 and then square it.

((3/8)/2)^2=(3/8*1/2)^2=(3/16)^2=9/256(382)2=(3812)2=(316)2=9256

Add this value to the left hand side

8(x^2+3/8x+9/256)=28(x2+38x+9256)=2

Add 8(9/256)8(9256) to the right hand side because of the factoring we did earlier.

8(x^2+3/8x+9/256)=2+8(9/256)8(x2+38x+9256)=2+8(9256)

You now have a perfect square trinomial

8(x+3/16)^2=2+8(9/256)8(x+316)2=2+8(9256)

Simplify

8(x+3/16)^2=2+cancel8(9/(cancel256 32))

Convert 2 to an improper fraction

8(x+3/16)^2=64/32+(9/(32))

Simplify

8(x+3/16)^2=73/32

y=8(x+3/16)^2-73/32

Vertex form

y=(x-h)^2+k where (h,k) is the vertex

Vertex (-3/16,-73/32)

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