same sigmd add and keep different signs subtract negative and negative make a positive and postive and negative make a negative you see
The answer to "12x-(4y+7z) for x=9 y= 4 and z = 2" is 78.
HCF= highest common factor
LCM= least common multiple
Where is the graph? Because it would be a lot easier to answer this if you could show a picture of the graph
