The property used is the Associative property
3 × 70 = 3(70) = 3 (7×10) = (3×7) ×10
The formula is
a × bc = a (bc) = a (b×c) = (a×b) ×c
Answer: 4xy and 3xy are, 2s and 5s are, but -10 and -10b aren't.
Step-by-step explanation: 4xy and 2xy have the same terms. 2s and 5s have the same terms but -10a and -10b have different variables.