SOLUTION: solve the system by graphing x+y=4 -x+y=2

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Question 110293: solve the system by graphing
x+y=4
-x+y=2

Answer by praseenakos@yahoo.com(507) About Me  (Show Source):
You can put this solution on YOUR website!
Question:
solve the system by graphing
x+y=4
-x+y=2
Answer:
To graph the system of equation manually, first you have to rewrite the given equation as a function of 'x' only, as follows,
y = 4 - x and
y = 2 + x (That is shifting all the terms other than y to the other side)

Now consider the first equation, y = 4 - x

Now give few values for x and find out the corresponding values of y
that is,
when x = 0, y = 4-0 = 4

when x = 1, y = 4-1 = 3

when x = -1, y = 4-(-1) = 5
when x = 2, y = 4-2 = 2

when x = -2, y = 4-(-2) = 6
when x = 3, y = 4-3 = 1

when x = -3, y = 4-(-3) = 7
and so on.........

Thus you have points,
(0,4), (1,3), (-1,5), (2,3), (-2,6), (3,1), (-3,7) etc.

Now plot these points on the graph paper, then you will get a straight line.

Similarly take the second equation and follow the same procedure and get the straight line.

Then the graph will come like this...

+graph%28+800%2C+800%2C+-9%2C+9%2C+-10%2C+10%2C+4-x%2C+2%2Bx%29+


From the graph you can see that, both the lines will intersect at a point.
Draw perpendiculars to both x and y axes.

Then then these perpendiculars will touch x= 1 on the x axis and y - 3 on the y axis, which is the required solution of the given equations.

that is , x = 1 and y = 3


Hope you found the explanation useful.

Regards.

Praseena.