Which number sentence shows the associative property of addition? choose all that apply. 2(4 · 3x) = (2 · 4)(3x) 11z + 9p = 9p + 11z 7 + (8 + 6) = (7 + 8) + 6 (17 + 11) + 3 = 17 + (11 + 3) i think c ?

It should be C and D. 

For the first one, 2(4 · 3x) = (2 · 4)(3x), we group the numbers differently but we get the same answer again when we multiply them. This shows the Associative Property of Multiplication.

For the second one, 11z + 9p = 9p + 11z where we get the same thing when we multiply them even if we switch the order, shows the Commutative Property of Multiplication.

For 7 + (8 + 6) = (7 + 8) + 6 and (17 + 11) + 3 = 17 + (11 + 3), we group the numbers differently but we still get the same answer when we add them. They show the Associative Property of Addition.