SOLUTION: I am trying to get through some problems....one of which is: y=x^2-6x+2 I'll be asking for many more but I will do one at a time. :) ~Jolene

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: I am trying to get through some problems....one of which is: y=x^2-6x+2 I'll be asking for many more but I will do one at a time. :) ~Jolene      Log On


   

Question 1919: I am trying to get through some problems....one of which is:
y=x^2-6x+2
I'll be asking for many more but I will do one at a time. :)
~Jolene
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
Jolene,
here goes...but please look at the previous answer i have given. I have done so many quadratics. Just take some time to read a couple...i do try to explain what i am doing, so you should then try it yourself and that way, by trying (and getting some wrong) you will learn it better :-)
I assume you want to have it solved? so, this means, what values of x when y=0...
x%5E2+-+6x+%2B+2+=+0
This does not factorise easily, so i will use te quadratic formula,
x+=+%28-b+%2B-+sqrt%28b%5E2+-+4ac%29%29%2F%282a%29
x+=+%28-%28-6%29+%2B-+sqrt%28%28-6%29%5E2+-+4%281%29%282%29%29%29%2F%282%2A1%29
x+=+%286+%2B-+sqrt%2836+-+8%29%29%2F%282%29
x+=+%286+%2B-+sqrt%2828%29%29%2F%282%29
Now you can either get your calculator out now and work out this to however many decimal places required or you can do the following...
now, as 28 can be written as 7x4, i shall write:
x+=+%286+%2B-+sqrt%287%29%284%29%29%2F%282%29
x+=+%286+%2B-+sqrt%287%29sqrt%284%29%29%2F%282%29
x+=+%286+%2B-+2sqrt%287%29%29%2F%282%29
x+=+%286+%2B+2sqrt%287%29%29%2F%282%29 or x+=+%286+-+2sqrt%287%29%29%2F2
so,
x+=+3+%2B+sqrt%287%29 or x+=+3+-+sqrt%287%29
these 2 answers are much neater than what your calculator gives you AND are the precise answers, not something rounded up by you.
Hope you followed this.
Try your own now :-D
cheers
Jon.