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Harder Trinomials - Undoing FOIL

Now, we need to find the first guys...

Our choices are:

1 * 4 and 2 * 2

Here's our list of possible combinations:

First: 1 * 4 and 4 * 1 and 2 * 2 , Last: 1 * 7
 

We need a middle guy of -16...

1) 1 * 4 and 1 * 7 ... the inner terms give 4 and the outer terms give 7 ... 4 and 7 cannot make a -16

2) 4 * 1 and 1 * 7 ... the inner terms give 1 and the outer terms give 28 ... 1 and 28 cannot make a -16.

3) 2 * 2 and 1 * 7 ... the inner terms give 2 and the outer terms give 14 ... -2 - 14 = -16

See if you can lock them in... I'll do it on the next page.