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Harder Trinomials - Undoing FOIL

Lock them in:

First: 2 * 2 and Last: 1 * 7 gives ( 2x - 1 ) ( 2x - 7 ) ... the inner terms give -2x and the outer terms give -14x

So,

4x^2 - 16x + 7 = ( 2x - 1 ) ( 2x - 7 )

Check with FOIL!

TRY IT:

Factor  12x^2 - 17x - 5

OK... Now let's leave the safe world of primes behind! Ready? Do you need an antacid or anything? If you start to hyperventilate at anytime, breathe into a paper bag.