Quadratic Inequality Help !!!!!!!!!!! (1 Viewer)

[MONKEYjulz]

Question:

[3(x+1)] / (x-1) is less than or equal to 2x
I was taught to times both sides by the denominator squared.
Why does the solution just bring the denominator across to the other side?
I have no idea. Can someone explain to me

THANKS

 

[Johanist]

this is because you don't know whether (x-1) is a positive or negative number, but whenever you square something you will always get a positive number even if pronumerals are involved. Also, because you don't know if its positive or negative you don't know whether you should change the sign or not, and when multiplying by a positive number the inequality sign doesn't change

 

[Bdogz]

this is because you don't know whether (x-1) is a positive or negative number, but whenever you square something you will always get a positive number even if pronumerals are involved.

Hence the inequality sign won't change sign if you times by a positive

 

[cutemouse]

You could also take cases... more annoying though.