If A = {1, 3, 5, 7, 9} and B = {2, 3, 5, 7}, what is A U B?

Ineed with number 17 i don’t get it at alll

What is the perimeter of an equilateral triangle if each side is (x+3)?

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: