### Box Method for Factoring 2.ppt

```Box Method for Factoring
Factoring expressions in the
form of ax2+bx+c
Box Method for Factoring


We are going to factor the expression 15x2 -7x-2
First draw a box and divide into quarters.
Box Method for Factoring




Now we are going to place the terms of
the expression into the box.
Look at the expression: 15x2 -7x-2
Place the 15x2 in the top left box.
Place the -2 in the bottom right box.
15x2
-2
Box Method for Factoring
15x2 -7x-2

Now we are going to multiply the
coefficient of the first term by the
constant. (15)(-2) = -30
15x2
-2
Box Method for Factoring
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
Now we are going to list the factors of 30.
30
1  30
2  15
3  10
5 6
Are there any pair of numbers that would equal -7?
Box Method for Factoring



We just found the factors of -30 that have
a sum of -7!
We will place those factors in the box with
an “x”
It doesn’t matter which box you put them
in.
15x2 -10x
3x
-2
Box Method for Factoring


Now we are going to pull out the common
factors from each row and column.
Last sign out of the box determines the sign.
3x
-2
5x 15x2 -10x
1
3x
-2
Box Method for Factoring


We now have the factors of 15x2 -7x-2
The factors are: (5x + 1)(3x - 2)
```