## January 10, 2012

### Today's lesson (10.01.12)

Hi class! Today we should have continued with the working group but yesterday we carry very badly and Mario was angered. Mario has explained the three cases there is for solving second degree equations.
First case:
For example: 4\$x^{2}\$-36=0
We have to clear x^2:
4\$x^{2}\$=0+36
\$x^{2}\$=36/4
\$x^{2}\$=9
And the value of x^2 is:
√(9 )=±3
Second case:
For example: 7\$x^{2}\$-6x=0
We remove the common factor:
x(7x-6)=0
The two solutions are:
x=0 x=6/7
Third case:
For example: 8\$x^{2}\$=0
The only solution for this type of equations is: 0.

And finally we have done an exercise with many steps to solve a quadratic equation, but Mario has told us that there is a formula that helps us to avoid having to do all these steps.
x=(-b±√(b^2-4ac))/2a
The homework is learn this formula. I hope you have understood it.

1. Nicely done Idoia!! :D

It's a shame that the LaTeX formulation doesn't work any more in blogger :'( I hope they'll find a way to sort this problem out soon ;)

Be seeing you!

2. When, at the beginning of the class when you gave us the paper to write the formula, I felt confused and I wrote a formula with colours and geometrical forms jajajjajaj!

Mario, the 4x4x4 is too dificult and I have to learn a very, very, VERY difficult and long algorithm...

3. I strongly recommend you not to learn it by heart, but to write it down and keep it forever XD

I can't learn it either... JAJAJAJ!

4. Mario do you know thw internet memes?
Forma ex: poker face, trollface, yao Ming...

5. Mario do you know thw internet memes?
Forma ex: poker face, trollface, yao Ming...

1. Dear Santi, I'm older than you, and I bet I discovered forever alone and company before you did XD

Hahahah!!! I love them!! XD

6. Of course jaja, I wasn't sure.

I love them too jajja

7. Mario I have a problem with the 4x4x4...

I know how to do it but when i finish, i have all the cube made in the good way except two yellow corners that they should be at the other position.

That happened to me with my 3x3x3 cube, but it was because the two corners fell and i put it in the wrong way. But it`s strange because your cube hasn`t fall at any moment.

I did the cube one time, but the next, the corners were changed.

8. Tristán, are you drunk? XD

SAnti, don't worry, it's not random but sometimes it happens to reach that moment when the corners should be one in the place of the other :) That's also colled the "Paridad" Problem, here you have a video with a HORRIBLE (don't try to learn it by heart) algorithm to solve it ;)

9. Ok Mario, i Washington vertical worried...

Yes i have heard about the paridad. Also itq happens some fines agencia you have ti do the yellow críes.

10. Uy sorry, the phone has write ir wrong.
I wanted to say i was very worried.

11. k bonito no??estar ahi amarrau

12. Mario esto es lo que hice yo en los 15 minutos ejjeje