Question 83950
Given:
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(6 + 8i) - (-7 + i)
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The first set of parentheses is preceded by a plus sign (you can presume that because 
there is no sign actually shown). Parentheses that are preceded by a + sign (or by no sign)
can be removed without any change to the terms they contain.  This changes the given
problem to:
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6 + 8i - (-7 + i)
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Notice that the remaining set of parentheses is preceded by a minus sign. The rule  is that
you can remove these parentheses if you change the signs of the terms inside the parentheses.
Following this rule leads to the given expression now becoming:
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6 + 8i + 7 - i
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Now you deal with the "regular" integer terms separately from the terms containing "i".
In other words you can combine the +6 and +7 to get +13. Then you add the 8i and the -i 
to get +7i.
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The answer to your problem is the combination of these two terms and it is:
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13 + 7i.
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Hope this helps you to work your way through this problem and helps you understand 
how the process works.
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