Chapter 8 - Polynomials and Factoring - 8-5 Factoring x2+bx+c - Practice and Problem-Solving Exercises - Page 516: 37

(m-7n)(m+4n)

You are given $m^{2}$-3mn-28$n^{2}$. Factor it out: $m^{2}$-7mn+4mn-28$n^{2}$ -break out the middle value- ($m^{2}$-7mn)+(4mn-28$n^{2}$) -group the first two and last two terms- m(m-7n)+4n(m-7n) -Find the GCF of each grouping- (m+4n)(m-7n) -factor out the common term- =(m+4n)(m-7n)