help me please??:/
What is the vertex form of the equation?
y = x^2 – 6x + 8

Question

help me please??:/
What is the vertex form of the equation?
y = x^2 – 6x + 8

campbell_st · Answer

well you need to complete the square in x

$$y = (x^2 - 6x + [\frac{6}{2}]^2) + 8 - (\frac{6}{2})^2$$

factor the perfect square and you'll have the vertex form

anonymous · Answer

can u help me do it?

campbell_st · Answer

well what is (6/2)^2 = ..?

anonymous · Answer

9?

campbell_st · Answer

yep so you have added 9 to complete the square and then subtracted 9 for 8

so you have

$$y=(x^2 -6x +9) + 8 - 9$$

factor the brackets.... its a perfect square...

then  8 - 9 = -1

so you will have 

$$y = (x - ?)^2 - 1$$

whats the value of ?

campbell_st · Answer

the vertex form is 

$$y = a(x -h)^2 + k$$

(h, k) is the vertex of the parabola. 

your final factored equation should look like it

hope this helps

anonymous · Answer

how do i find the one thats missing in y = x - ?)^2 -1?

campbell_st · Answer

well you need to factor the quadratic

$$x^2 -6x + 9$$

what factors of 9 add to 6.. that will be ?

anonymous · Answer

a factor of 9 is 3, and 3+3 = 6..?

campbell_st · Answer

yep... so thats the ? 

its 

$$y = (x -3)^2 -1 $$

thats the vertex form

anonymous · Answer

and thats the answer?

campbell_st · Answer

thats it

anonymous · Answer

thank you soo much!!:D