SOLUTION: determine the unknown value of two of three addends are 5 and -7. If the sum of three numbers is 21,what is the third addend?

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Question 31460: determine the unknown value of
two of three addends are 5 and -7. If the sum of three numbers is 21,what is the third addend?

Answer by mukhopadhyay(490) About Me  (Show Source):
You can put this solution on YOUR website!
Let the unknwown addend be x
x+5+(-7)=21
=>x-2=21
=>x=23
The unknown addend is 23.