y = x^2 - 6x +8 = 0: solve two ways

[Guest]

I haven't been in a math class in a REALLY long time. If someone could help me with these problems I would really appreciate it.

Using the quadratic equation y = x^2 - 6x + 8 = 0, perform the following tasks:
Solve by completing the square.
Solve by using the quadratic formula.

I have about eight more just like this. Maybe if I can get this one I will be able to get the rest on my own! Thanks

 

[galactus]

Hello kinerry.

For completing the square:

\(\displaystyle \L\\x^{2}-6x+8=0\)

\(\displaystyle \L\\x^{2}-6x=-8\)

Take half the coefficient of x and square it, add it to both sides:

\(\displaystyle \L\\x^{2}-6x+9=-8+9\)

Factor:

\(\displaystyle \L\\(x-3)^{2}=1\)

\(\displaystyle \L\\x=2\;\ or\;\ 4\)

If the leading coefficient is something other than 1, it can be a little trickier.
Do you have any like that?.

 

[Guest]

quadratic

Thank you for the help with the square. I got it (I think). I still need help doing the quadratic equation part though. How do you write it out in quadratic form ? It makes no sense. I don't havean example with a negative for A in my textbook.

 

[stapel]

Re: quadratic

I still need help doing the quadratic equation part though.

Do you mean "the solving by using the Quadratic Formula" part...?

How do you write it out in quadratic form?

Please provide your book's definition of "quadratic form". Thank you.

I don't have an example with a negative for A in my textbook.

The sign on "a" is not relevant. Just plug the value, positive or negative, into the Quadratic Formula, as explained and demonstrated in your text.

Eliz.

 

[Guest]

quadratic formula

yes I did mean the quadratic formula. I don't understand how to do the quadratic formula steps for this problem

 

[Denis]

Do you know what the quadratic formula is?
If not, why did you not look it up?