Tuesday, February 1, 2011

2x + 3y = 2 and 5X - 5y = 10 solve for x and y

It is easy to see that, the second equation, after
factorization, will look
like:


5(x-y)=10


We'll divide
it by 5 and we'll
get:


x-y=2


The first equation
looks like:2x + 3y = 2


We'll try to reduce the unknown y,
by multiplying the equation x-y=2 by 3 and, after that, we'll add it to the equation 2x
+ 3y =
2.


3x-3y+2x+3y=6+2


After
reducing the terms 3y and -3y, we'll
get:


5x=8


x= 8/5
= 1.6


Now, we'll find out y by substituting
x into the
equation:


x-y=2


1.6 - y =
2


We'll subtract 1.6 both
sides:


-y = 2 - 1.6


-y =
0.4


We'll multiply both sides by
(-1).


y=-0.4

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