Friday, June 20, 2014

What are solutions of simultaneous equations 1/x=(y-1)/y 3/x=(2y-1)/y

We'll re-write the given equations by cross
multiplying:


y = x(y-1)


We'll
remove the brackets:


y = xy -
x


We'll add x both sides:


x +
y = xy (1)


We'll change the 2nd equation
in:


3y = x(2y-1)


3y = 2xy -
x


We'll add x both sides:


3y +
x = 2xy (2)


We'll substitute (1) in
(2):


3y + x = 2(x+y)


3y + x =
2x + 2y


3y - 2y = 2x - x


y = x
(3)


We'll substitute (3) in
(2)


3x + x = 2x^2


4x =
2x^2


We'll divide by 2 and we'll use the symmetric
property:


x^2 - 2x = 0


We'll
factorize by x:


x(x-2) = 0


x =
0


x-2 = 0


x =
2


So, because x = y => y =
2


The solution of the system is {2 ;
2}.

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