Explanation:
Let's substitute with each variable.
Task : Verify a + (b + c) = (a + b) + c [Associative Property]
(I) a = 2 , b = 0 , c = -9
2 + (0 + (-9)) = (2 + 0) + (-9)
2 + (-9) = 2 + (-9)
-7 = -7 (Proved)
(II) a = 34 , b = 90 , c = -1
34 + (90 + (-1)) = (34 + 90) + (-1)
34 + 89 = 124 + (-1)
123 = 123 (Proved)
a + (b + c) = (a + b) + c is true for any real number.
Subject : Mathematics
Level : ES
Chapter : Number Property