Question 45132
This is what I call "Advanced Trinomial Factoring", and I have a lesson specifically for this topic on my website under "Basic Algebra", then go to "Samples from Basic Algebra: One Step at a Time", then "Chapter 2".


Anyway, notice that the middle term is 79x which is an odd number.  This means that the First times First cannot be both EVEN numbers.  It has to be 16 times 1.  


So (16x  ____)(x  ___ )


Now the Last times Last must be 1 times 5 or 5 times 1.  In order to get a large number like 79 in the middle term, you will have to place the 5 so it multiplies times the 16 like this:

{16x - 1)(x+5)


FOIL it out, and it works!!


(16x-1)(x+5) = 16x^2 + 79x - 5 


R^2 at SCC