Answer this question on the picture

Can someone show me step by step how to do this?

Plzz ! if you were constructing a triangular frame, and you had wood in the length of 4 inches, 4 inches, and 7 inches, would it make a triangle? would you be able to create a frame from these pieces of wood? yes or no? = explain your mathematical thinking/show your work:

24m^2n+30mn^2+18mn, a sweet challenge!