completing the square

[mollykins]

I can do some of them, but on mymaths, there are questions that involve ending up with fractions, but we haven't ben taught how to do these, and the online tutorial doesn't include any that do . . . . can anyone help?

[squarebear]

Your teacher?

[anneasquith]

no sorry . molly.

[mollykins]

*been*

She's ill, but we need to do it by friday . . . .

[berniecuddles]

Oh NO RUN TO THE HILLS EVERYBODY!!

[anneasquith]

google ?

[mollykins]

I can't find one's that involve the answer being in the form of a number then the square root of a number, over another, only the simpler ones I can do.

[berniecuddles]

why would you get questions about something that you havent been taught about!
yes here we go again "the strange world of molly in 100 answers"

[mollykins]

I don't think she realised the questions started to involve stuff we hadn't done, it's only the last 1/4.

[society]

I don't understand Molly, if your teacher is ill and hadn't taught 'that' lesson how the heck she expects the class to know it.

[squarebear]

How can you do them if you haven't been taught?

[sherrardk]

Don't do them. When she asks why they aren't done, tell her it's because you haven't been taught how to do them.

[berniecuddles]

wait for it????

[jomifl]

could you give us slightly more of a clue as to what your problem is because at the moment it could be almost anything involving maths..probably.

[Prudie]

Post an example

[anneasquith]

E,G,

[Mamyalynne]

http://www.algebrahel...50k^2+-+20k+-+6+%3D+0
.

[bibblebub]

perhaps the teacher wants to see if anyone is going to show some initiative

[vascop]

Molly
There's no difference between the methods for completing the square when the numbers turn out to be fractions and when they don't. So as long as you can manipulate fractions you should be OK.
Just remember that sqrt(a/b)=sqrt(a)/sqrt(b) and sqrt(a x b)=sqrt(a) x sqrt(b).
so sqrt(9/4)=sqrt(9)/sqrt(4)=+/-3/2 etc.
Also squaring fractions (a/b)^2=a^2/b^2 etc

[mollykins]

Bibble, the thing is, half my class are resitting this, so they already know how to do it, but the rest of us have only been taught how to do the basics of it, and non end up like mymaths is expecting the format to be. (if that makes sense)

[mollykins]

one of the one's i got when i clicked on it this time (they change every time you go on it) was; 16x^2-72x-9=0 and because it's online it gives you the format of the answer and you have to fill the boxes in, for this one it's x=[ ] +/- sqrt [ ] divided by [ ]