Question 189148: I should solve this equation
9/(x+1) - 2/(x-2) = 5/(x+1)
I can solve it but it says check all proposed solutions! What does it mean?
Answer by vleith(2983)   (Show Source):
You can put this solution on YOUR website! Once you solve for all x that 'work', you need to check those values to ensure they do not end up being an invalid answer.
For instance, if x = -1 or x=2 end up being solutions for this problem, then you can't use them. Both of those values result in a denominator that is 0.
This applies to every problem. When you solve for roots, all you get are 'possible' answers. You always need to take a look at those possible answers to verify that they are, in fact, valid.
Another common place where a possible answer is invalid are problems that ask for the 'length' of something. Many times, the possible solutions will include at least one negative value. Since a 'length' can't be negative, those answers are invalid too.
Hope that helps
|
|
|
