Answer:
3d(5-4cd)
Explanation:
15d - 12cd² (we see that the highest common factor of 15 and 12 is 3, hence we can factor 3 out)
= 3 (5d - 4cd²) (we also notice that d appears in both terms in the parantheses. hence we can also factor d out)
= 3d(5-4cd)