Solve simple quadratic equations after factoring by the box method

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Edit   Delete - Last Modified By: bjo at 15/10/2013 9:56:26 AM

Check out this YouTube on the box method (OK, I know its daggy, but hey, it works!)

Edit   Delete - Last Modified By: bjo at 15/10/2013 10:01:43 AM
Here's another Tuber, and its a bit more formal...
Edit   Delete - Last Modified By: bjo at 15/10/2013 10:22:22 AM

Here's another way of looking at the box method - without the box!  This is called the criss-cross method.  It's essentially the same.

Edit   Delete - Last Modified By: bjo at 15/10/2013 10:23:24 AM
(did you hear the dog?)
Edit   Delete - Last Modified By: BJO at 25/10/2013 2:50:19 PM
Here is another explanation of the box method
Edit   Delete - Last Modified By: BJO at 28/10/2013 10:16:44 AM

Log in to Manga High  (www.mangahigh.com) and go to 'mytodolist' tab.  Please attempt the following challenges:

  • Factorise quadratics in form x2 + bx + c
  • Factorise quadratics in form ax2 + bx + c

Go to Mangahigh

Edit   Delete - Last Modified By: BJO at 28/10/2013 10:14:19 AM

Remember: expanding two binomials (equations with two terms like 3x + 4) will give you a quadratic.  For example  (x + 5)(x - 1), using FOIL (first, outer, inner, last) will give a trinomial (an equation with three terms):

x2 - x + 5x - 5  = x2 + 4x - 5

If I was just given this last equation, how could I find out what its factors are?

- use the box method.

Here is a powerpoint presentation (that will be run in class).  When it is presented, you might want to have downloaded it, and have it open on your netbook so that you can follow it and take notes.

Edit   Delete - Last Modified By: bjo at 15/10/2013 10:15:51 AM
If you want to see some more examples, check out the vids in the anytime anywhere section.