Question 733137
M^2+8m+7

8m is split as m +7m 
m^2 + m + 7m +7
Group first two terms and last two terms together

(m^2+M) + (7m + 7)
m(m+1) + 7(m+1)


take the common term m+1
(m+1)(m+7)


M= -1, -7