**I. The final page of factoring problems in the University of Chicago Math Project Algebra textbook (Chapter 12 of 13 chapters)** [click to enlarge]:

**II. The final page of factoring problems in Wentworth's**[click to enlarge]:

*New School Algebra*textbook (Chapter 7 of 17 chapters)**III. Extra Credit**

What do the University of Chicago Math Project students miss out on by not having problems as challenging as problem #121 above?

What did Wentworth's students miss out on by not having SPUR Objectives, where, once again:

## 1 comment:

Boy, I really got off track into the weeds with that last one until I saw the trick.

x^4 - 2abx^2 - a^4 - a^2b^2 - b^4

= (x^4 - 2abx^2 + a^2b^2) - (a^4 + 2a^2b^2 + b^4)

= (x^2 - ab)^2 - (a^2 + b^2)^2

But m^2 - n^2 = (m + n)(m - n), so we have:

= [(x^2 - ab) + (a^2 + b^2)][(x^2 - ab) - (a^2 + b^2)]

= (x^2 - ab + a^2 + b^2)(x^2 - ab - a^2 - b^2)

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