<PRE><B>Question 67356</B>
TO SOLVE THESE PROBLEMS YOU NEED TO SUBSTITUTE THE (X,Y) VALUES INTO THE EQUATION AND SEE IT (X-Y)=4 IF THEY DO NOT THEN THE (X,Y) VALUES ARE NOT VALID.
IF (X-Y)=4 THEN THES ARE SOLUTIONS.
3-1=4
2 DOES NOT EQUAL 4 NOT A SOLUTION
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0-(-4)=4
4=4 THIS SET IS A SOLUTION
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-4-0=4
-4 DOES NOT EQUAL 4 NOT A SOLUTION
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-3-(-7)=4
-3+7=4
4=4 THIS ALSO IS A SOLUTION
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