using the ac method to factor

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c bx x 2

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Using the AC method to factor. When factoring x^2+bx+c, sometimes there can be many factors of c. Example: Factor. If you recall, if a =1 then we factor c and we look for the pairs of factors that sum to the middle term, b. - PowerPoint PPT Presentation

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Page 1: Using the AC method to factor

cbxx 2

Page 2: Using the AC method to factor

When factoring x^2+bx+c, sometimes there can be many factors of c

Example: Factor 44292 xxIf you recall, if a =1 then we factor c and we look for the pairs of factors that sum to the middle term, b

So we want to find the factors of 442 that add up to -9. There are many factors of 442 so let’s use our calculator to help us.

Page 3: Using the AC method to factor

In this case, we want to find the factors of 442

Press the following sequence of buttons on your calculatorsY=, 442, /, x, 2nd, GRAPH

Page 4: Using the AC method to factor

You should see the following on your screen (before pressing 2nd GRAPH)

After pressing 2nd GRAPH you should see something like this:

If you don’t see this, then go to the next slide for trouble shooting. If you do see this, then skip the next slide.

Page 5: Using the AC method to factor

Press 2nd, then WINDOW

You should see the following

Set your independent to Auto, your table start at 0, and your triangle table = to 1v

Now press 2nd and then GRAPH

Then you should see what we got before

Page 6: Using the AC method to factor

Scroll down to look through the factors. We are looking for the pair that add OR subtracts to -9

The only pair that this can happen with is 17 and 26. Since we want it to add to -8, the factors should be -26 and +17

So therefore, our factors are: 2617 xx

Multiply it out to make sure that it checks!