SOLUTION: Please help me solve this equation: {{{ x/(x+1)-2=3/(x-3) }}}

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Question 268825: Please help me solve this equation: +x%2F%28x%2B1%29-2=3%2F%28x-3%29+
Found 4 solutions by mananth, jsmallt9, ikleyn, n2:
Answer by mananth(16949) About Me  (Show Source):
You can put this solution on YOUR website!
x/(x+1)-2=3/(x-3)
x-2x-2 = 3(x+1)/(x-3)
-x-2= 3x+3 /x-3
(x-3(-x-2)= 3x+3
-x^2-2x+3x+6=3x+3
-x^2-2x+3=0
x^2-2x-3=0
x^2-3x+x-3=0
x(x-3)+1(x-3)=0
(x-3)(x+1)=0

Answer by jsmallt9(3759) About Me  (Show Source):
You can put this solution on YOUR website!
(NOTE: There is an error in a solution provided by another tutor.)

+x%2F%28x%2B1%29-2=3%2F%28x-3%29+

We'll start by eliminating the fractions. This is done by multiplying both sides of the equation by the lowest common denominator (LCD). The LCD here is (x+1)(x-3). Multiplying both sides by the LCD we get:
%28x%2B1%29%28x-3%29%28+x%2F%28x%2B1%29-2%29=%28x%2B1%29%28x-3%29%283%2F%28x-3%29%29+
On the left side we need to use the Distributive Property:

Now we can cancel factors:

%28x-3%29%28+x%29-%28x%2B1%29%28x-3%292=%28x%2B1%29%283%29
Now we can multiply. (Pay close attention to the minus sign in the middle of the left side!)
x%5E2+-+3x+-+%28x%5E2+-2x+-+3%292+=+3x%2B3
x%5E2+-+3x+-+%282x%5E2+-4x+-+6%29+=+3x%2B3
x%5E2+-+3x+%2B+%28-2x%5E2%29+%2B4x+%2B+6+=+3x%2B3
-x%5E2+%2Bx+%2B+6+=+3x+%2B+3
The fractions are gone. Now we have a quadratic equation to solve. We start by making one side zero (by subtracting 3x and 3 from each side):
-x%5E2+-2x+%2B+3+=+0
To make the factoring easier I'm going to multiply both sides by -1:
x%5E2+%2B2x+-+3+=+0
Now it factors into
%28x%2B3%29%28x-1%29+=+0
According to the Zero Product Property this product can be zero only if one of the factors is zero. So:
x%2B3+=+0 or x-1+=+0
Solving these we get:
x+=+-3 or x+=+1

We should check our answers. It is more than a good idea to check our answers in this problem because when we multiplied both sides by the LCD and, depending on the value for x, the LCD might be zero. And whenever you multiply both sides by something that might be zero you may get answers that don't actually fit the original equation. So we must check.
+x%2F%28x%2B1%29-2=3%2F%28x-3%29+
Checking x = -3:
+%28-3%29%2F%28%28-3%29%2B1%29-2=3%2F%28%28-3%29-3%29+
+%28-3%29%2F%28-2%29-2=3%2F%28-6%29+
+3%2F2-+4%2F2=-1%2F2+
+1%2F2=-1%2F2+ Check!

Checking x = 1:
+%281%29%2F%28%281%29%2B1%29-2=3%2F%28%281%29-3%29+
+1%2F2-2=3%2F%28-2%29+
+1%2F2-+4%2F2=-3%2F2+
+-3%2F2=-3%2F2+ Check!


Answer by ikleyn(53712) About Me  (Show Source):
You can put this solution on YOUR website!
.
Please help me solve this equation: x%2F%28x%2B1%29%29-2 = 3%2F%28x-3%29
~~~~~~~~~~~~~~~~~~~~~~~~~~


        The solution in the post by @mananth is INCORRECT.

        His transformations, which he performs to reduce the given equation to the factored quadratic equation,
        contain a lot of arithmetic errors, and his final equation is wrong.

        The answer absents in his solution.  So, his presentation is a compote of mathematical symbols
        with no mathematical sense,  which may lead a reader to wrong conclusion.

        Therefore,  I came to bring a correct solution.


Your starting equation is 

    x%2F%28x%2B1%29%29-2 = 3%2F%28x-3%29.


The domain of this equation is the set of all real numbers except of x= -1 and x= 3.
We will work over the domain, assuming that x =/= -1  and  x =/= 3.


Multiply both sides by LCD (x+1)*(x-3) and simplify

    x*(x-3) - 2(x+1)*(x-3)  = 3(x+1),

    x^2 - 3x - 2*(x^2 +x - 3x - 3) = 3x + 3,

    x^2 - 3x - 2x^2 - 2x + 6x + 6 = 3x + 3,

    -x^2 - 2x - 3 = 0,

    x^2 + 2x + 3 = 0,

    (x+3)*(x-1) = 0.


The solutions to this equation are the numbers -3 and 1.

They both are in the domain of the given equation,

so the solution to equation (1) are  x = -3  and  x = 1.

Solved completely and correctly.


/\/\/\/\/\/\/\/\/\/\/\/\/


Here is my general impression about the solutions by @mananth at this forum.

I just learned several months ago, that @mananth systematically uses a computer code,
which generates files with solutions.

In many cases (approximately in 10% of cases) the solutions generated by his computer code are incorrect.

But @mananth never reads and never checks what his code produces, so @mananth
does not carry any responsibility for the quality of his solutions.

Any reader should understand it - - - @mananth does not carry any responsibility for the correctness
of his solutions: this is his principial position.

Factually, he leaves this responsibility to those tutors (like me),
who check every, each and all his solutions totally.



Answer by n2(72) About Me  (Show Source):
You can put this solution on YOUR website!
.
Please help me solve this equation: x%2F%28x%2B1%29%29-2 = 3%2F%28x-3%29
~~~~~~~~~~~~~~~~~~~~~~~~~~


Your starting equation is 

    x%2F%28x%2B1%29%29-2 = 3%2F%28x-3%29.


The domain of this equation is the set of all real numbers except of x= -1 and x= 3.
We will work over the domain, assuming that x =/= -1  and  x =/= 3.


Multiply both sides by LCD (x+1)*(x-3) and simplify

    x*(x-3) - 2(x+1)*(x-3)  = 3(x+1),

    x^2 - 3x - 2*(x^2 +x - 3x - 3) = 3x + 3,

    x^2 - 3x - 2x^2 - 2x + 6x + 6 = 3x + 3,

    -x^2 - 2x - 3 = 0,

    x^2 + 2x + 3 = 0,

    (x+3)*(x-1) = 0.


The solutions to this equation are the numbers -3 and 1.

They both are in the domain of the given equation,

so the solution to equation (1) are  x = -3  and  x = 1.

Solved completely and correctly.