Can someone help me with this math problem

B. (m-1)(m-8)

Step-by-step explanation:

The factors of 8 (constant term) are

{(1,8), (2,4)}, from which we see that 1+8 = 9, the absolute value of the coefficient of the second term.

Therefore we can group the expression as

m^2 - 9m + 8

= m^2-m - (8m -8)

then factor each group

= m(m-1) - 8(m-1)

and factor out (m-1)

= (m-1)(m-8)