multiple choice test: dont know the steps

Eva Barragan

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Joined
Feb 8, 2006
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the derictions say: What is the solution set for the equation?
the problem is: x^2-6x+4=0
the choices are:{-3=sqrt5}
{3=sqrt5}
{-3=2sqrt5}
{3=2sqrt5}
those ar the possible awnsers i have no idea how you can get any of these awnsers for that problem
your help would really be appreciated
thanks :cry:



p.s on the test there is a straight line going through the equal sighn i didnt know how to right it
 
our teacher said it was ok to go on this website for help
but i understand where your coming from
thanks anyway
:(
 
Eva Barragan said:
What is the solution set for the equation x<sup>2</sup> - 6x + 4 = 0?
What did you get when you plugged this into the Quadratic Formula? Please show all of your steps.

Eva Barragan said:
[T]here is a straight line going through the equal [sign. I didn't] know how to [write] it[.]

Do you not know what that symbol means...?

Through which of the "equals" signs is there a "not" slash?

Thank you.

Eliz.
 
Eva Barragan said:
the derictions say: What is the solution set for the equation?
the problem is: x^2-6x+4=0
the choices are:{-3=sqrt5}
{3=sqrt5}
{-3=2sqrt5}
{3=2sqrt5}
those ar the possible awnsers i have no idea how you can get any of these awnsers for that problem
your help would really be appreciated
thanks :cry:



p.s on the test there is a straight line going through the equal sighn i didnt know how to right it


Hmmmm.....I wonder if your "mysterious sign" is really +, which means "plus or minus".

For example, 3 + sqrt(5) is a short way to write "3 + sqrt(5) OR 3 - sqrt(5)"

So, each of your choices for a solution set actually contains two values.

Next, if you have a quadratic equation of the form
ax<SUP>2</SUP> + bx + c = 0
you can always use the quadratic formula to find the solutions. By the quadratic formula,

xxxx -b + sqrt(b<SUP>2</SUP> - 4ac )
x = ___________________
xxxxxxxxxxxxx2a


Now, your equation is
x<SUP>2</SUP> - 6x + 4 = 0

a = 1, b = -6, and c = 4

Substitute into the quadratic formula:
xxxx -(-6) + sqrt[(-6)<SUP>2</SUP> - 4(1)(4)]
x = _____________________
xxxxxxxxx2(1)

Do the arithmetic; you'll get a fraction which can be simplified. See which answer choice matches.
 
ummmm im done with the test already but thanks anyway
mrspi: i couldnt figure out what the sighn ment but it wasnt this + with a line under it
thanks for your help
eliz i did end up using the quadratic eqation i think it worked
zero degrees thanx the qudratic equation did work :D
thank you all really appreciate it
i still dont understand how to do these kinda problems though
can you guys please explain the steps to me
thanx all your help was much appreciated
 
Eva Barragan said:
ummmm im done with the test already but thanks anyway
mrspi: i couldnt figure out what the sighn ment but it wasnt this + with a line under it
thanks for your help
thanx all your help was much appreciated

I don't know what to tell you here....using the quadratic formula to solve your equation WILL give you this:

x = 3 + sqrt(5)

So I do firmly believe that your mysterious sign MUST HAVE BEEN "plus or minus". It makes absolutely no sense for it to be anything else.

But what do I know....in this magical cyber-world, maybe the rules of mathematics have gotten different.
 
*****zero re-focusing*****


ok, i will try a divergent explanation.

if you look up the quadratic formula in your book, it will start with x=, and then a bunch of a,b, and c variables. follow so far?

now think about the concept of the x= for a minute.you have a unfactorable trinomial, which means you have a value for x-squared AND a value for x(well, usually.....). two values for two diferent variables both named x. (x and x squared)

THAT'S why you cannot readily substitute the values for x into any formula the way it is now, because you have two values for x (x and x squared)

what you would need to do is to translate both values into completely new variables, namely a and b. now you can both differentiate between x and x-squared and substitute precisely.

we will make a=coefficient for x-squared, the varialbe with the highest degree.. we will make b-coefficient for x the varialbe with the lowest degree. since we are at it, we will label c=constant , the one lonely number with no varialbe at all.

Since it is a formula, once you have labeled a, b, and c, feel free to substitute all three values in the equation and simplify until con't simplify any more.


get used to this , this particular idea comes back into play for about half of the geometry course.


:idea:
 
thanx zero!
i love the way you explain the qudratic equation
my teacher did tell me i would use this formula in geomatry alot



mrspi maybe it was an equal sighn or a MINUS sighn but bottom line i didnt get it then but with zeros explanation and the explanation you gave me before i understand it know
thanx
 
thanx zero!
i love the way you explain the qudratic equation
my teacher did tell me i would use this formula in geomatry alot



mrspi maybe it was an equal sighn or a MINUS sighn but bottom line i didnt get it then but with zeros explanation and the explanation you gave me before i understand it know
thanx
 
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