true statements:
a) x + y = y + x ⇒ commutative property of addition
b) (x * y) * z = x * (y * z) ⇒ associative property of multiplication
d) (x + y) + z = x + (y + z) ⇒ associative property of addition
false statements:
c) x - y = y - x should be: x - y = - y + x
e) (x - y) - z = x - (y - z) should be: (x - y) - z = x - (y + z)
step-by-step explanation: