Answer:
(m - 11)(m + 5)
Explanation:
Factor: m^2 - 6m - 55.
Notice that -55 is the product either of -5 and 11 or of 5 and -11.
Notice that -11 + 5 = -6, which is the coefficient of the middle term (-6m).
Factoring by grouping, we get:
m^2 - 6m - 55 = m^2 - 11m + 5m - 55.
Notice that we can factor m out of the first two terms and can factor 5 out of the last two terms: m(m - 11) + 5(m - 11).
m - 11 is a factor of both m(m - 11) + 5(m - 11), and so
m(m - 11) + 5(m - 11) = (m - 11)(m + 5)