Question 301924
You need to factorise first : 

m^2 - 16 = (m+4)(m-4)
m^2 + 4m - 32 = (m+8)(m-4)

Put the answers into your fractions:

(m+4)(m-4)/ 3m * (m^2)/(m+8)(m-4)

simplify the fractions where possible:

=(m+4)/3 * m / (m+8)

= m(m+4) / 3(m+8)