Given,

3m² + 24m + 36

Now first find the numbers whose-

Sum = 24 and

Product = 36 × 3 = 108

Required numbers are 18 and 6,

So we get;

3m² + 24m + 36

= 3m² + 18m + 6m + 36

= 3m(m + 6) + 6(m + 6)

= (m + 6)(3m + 6)