Answer:The third one is!!
Step-by-step explanation:
The commutative property of addition says that changing the order of addends does not change the sum. Here's an example: 4 + 2 = 2 + 4 4 + 2 = 2 + 4 4+2=2+4
Answer:
x^4 - 81 = 0
(x² - 9)(x² + 9) = 0
Notice that the first of these is itself a difference of two squares:
(x - 3)(x + 3)(x² + 9) = 0
So the solutions are x = 3, x = -3, x = 3i, x = -3i
