## Introductory Algebra for College Students (7th Edition)

False. The statement could become true if we write: $a^{2}+b^{2}$ can not be factored.
First step: adding 0 = ab-ab does not change the result (OK). Second step: ERROR in factoring of the second group. It should read: $=a(a+b)-b(a-b)$ So the next step does not follow, since there is no common binomial to extract. (no factorization possible)