SOLUTION: dap5654@aol.com. I am in intermediate algebra. I am having trouble with equations with rational expressions. Could you help me solve this equation? {{{x/3 = 4/(x +1)}}}? I think

Algebra ->  Rational-functions -> SOLUTION: dap5654@aol.com. I am in intermediate algebra. I am having trouble with equations with rational expressions. Could you help me solve this equation? {{{x/3 = 4/(x +1)}}}? I think       Log On


   

Question 200602: dap5654@aol.com. I am in intermediate algebra. I am having trouble with equations with rational expressions.
Could you help me solve this equation? x%2F3+=+4%2F%28x+%2B1%29? I think the answer is 3,4.
Found 2 solutions by nerdybill, solver91311:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
x%2F3+=+4%2F%28x+%2B1%29
Cross multiplying we get:
x%28x+%2B1%29+=+3%2A4
x%5E2%2Bx+=+12
x%5E2%2Bx-12=0
Factoring:
%28x%2B4%29%28x-3%29=0
x = {-4,3}

Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


If you think the solution to an equation is a particular number, then the quickest way to make sure is to substitute that number back into the equation and see if you have a true statement.

You think that one of the roots is 3:



.

That one checks. Now let's try 4:



.

Oops. I guess we have to go back to the beginning.



Step 1: Cross multiply:



Step 2: Standard form of the quadratic:



Step 3: Factor:

and , so:



Step 4: Zero Product Rule:

or



We have already checked 3, so lets try -4:



. Checks.

What's the lesson? Slow and steady, step by step. And never stop at "I think..." You aren't done until you are sure.

John