What is the missing reason in the proof?
prove –(–y – x) – x = y
–(–y – x) – x = –[–y +(–x)] – x
definition of subtraction
–[–y +(–x)] – x = y + x – x
opposite of a sum property
y + x – x = y + x + (–x)
definition of subtraction
y + x + (–x) = y + [x + (–x)]
associative property of addition
y + [x + (–x)] = y + 0
additive inverse property
y + 0 = y
(blank)
answer options for (blank):
a. symmetric property
b. additive inverse property
c. additive identity property
d. opposite of a sum property