How do you solve the inequality x^2(x-3)(x+1)/(x-5)(x+7) or = to 0.... using a number line.

Question

How do you solve the inequality x^2(x-3)(x+1)/(x-5)(x+7) > or = to 0.... using a number line.

anonymous · Answer

$\dfrac{x^2(x-3)(x+1)}{(x-5)(x+7)}\geq0$
One step would be to figure out which values for x make this inequality undefined.

anonymous · Answer

sorry there is a network error but the first thing to do, you need to cross multiply

anonymous · Answer

cross multiply? I plugged points in on a number line (-7, -1, 0, 3 and 5) I just need to figure out which sections I need to shade in

anonymous · Answer

I will admit that I'm not sure how to solve this problem yet, but I don't see how cross multiplication will work.

anonymous · Answer

are you still there buddy, it seems everthing is okay now

anonymous · Answer

The original poster closed the question, but I am still curious about the answer....

anonymous · Answer

do you now how to get those values that poster got

anonymous · Answer

Yes, set each factor equal to 0.

anonymous · Answer

5 and -7 make the inequality undefined, so those should be open circles.

anonymous · Answer

so after that, you subtitude you values into the equation you got after cross multiplication

anonymous · Answer

I still don't understand how cross multiplication works in this case.

anonymous · Answer

|dw:1378598724942:dw|, your number line will be like this

anonymous · Answer

sorry G, what do you mean you still dont understand how cross multiplication comes in this case

anonymous · Answer

hey K, are you there

anonymous · Answer

Cross multiplication usually means multiplying across the equal sign. In this case, that would end up with 0=0.

anonymous · Answer

no, if you cross multiply$$x^2(x-3)(x+1)=0$$

anonymous · Answer

Right, because the fraction would be $\dfrac{0}{1}$ and not $\dfrac{0}{0}$. Got it now. Thanks.

anonymous · Answer

good, i think now we can carry on

anonymous · Answer

K are you there