Answer:
Step-by-step explanation:
(+)(+) = (+)
(-)(+) = (+)(-) = (-)
(-)(-) = (+)
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(-1) + (+8)= (-1) + 8 <em>use the commutative property a + b = b + a</em>
= 8 + (-1) = 8 - 1 = 7
You can do it
i am edditing my post because i got the answer wrong
