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.