Posted by Anonymous on .
If (x,7) is a solition to the equation 5xy=3, what is the value of x?

MATH 
SAM,
5XY=3
5X 5X
Y=35X
DIVIDE BY 1 ON BOTH SIDES
Y=3+5X
PLUG IT IN PLUG IT IN
7=35(X)
SOLVE
SUBTRACT BY 3 ON BOTH SIDES 4=5X
AND DIVIDE BY 5 ON BOTH SIDES 4/5=5/5X
4/5=X 
MATH 
SAM,
CORRRECTION!!!!
4/5! 
MATH 
X,
Here, all you have to do is substitute (7) for (y) in the equation. You can do this because all coordinates are of the form (x,y), and any number that is in the place of (y) in this format can be seen as equal to (y).
The working is shown below:
5x  (7) = 3
5x = 10
x = 2
As shown in the working above, x = 2 when y = 7.