Find the set of values for which: 3/(x+3) >(x-4)/x

First we must consider for which values of x the equation: 3/(x+3) = (x-4)/x is undefined. In this case, x=-3, and x=0. 

Now we must consider each of the cases, x<-3, -3<x<0, 0<x

Case 1 (x<-3): if we assume 3/(x+3) > (x-4)/x then it follows, as x<-3, 3x > x2-x-12. Which implies (x-6)(x+2) < 0. For this to hold exactly one of (x-6) and (x+2) must be less than 0 and the other greater than 0. which implies -2<x<4, which is a contradiction therfore not satisfied in the range.

Case 2 (-3<x<0)  x2-4x-12 > 0, which implies (x-6)(x+2) >0. Therefore for x2-4x-12 > 0, either both (x-6) and (x+2) must be less than 0 or greater than 0. therefore x<-2 or x>6. Therefore as we know -3<x<0, it holds for -3<x<-2

Case 3 (x>0): Therefore x2-4x-12 < 0, which implies (x-6)(x+2) < 0. For this to hold exactly one of (x-6) and (x+2) must be less than 0 and the other greater than 0. which implies -2<x<4, thefore the equation holds for 0<x<4

Finally as we have considered all cases the final answer is -3<x<-2 & 0<x<4.

DM
Answered by David M. Further Mathematics tutor

6016 Views

See similar Further Mathematics A Level tutors

Related Further Mathematics A Level answers

All answers ▸

How do I sketch accurate graphs for rational functions in a short amount of time? (I.e. A step by step guide of sketching graphs)


Split x^4/[(x^2+4)*(x-2)^2] into partial fractions and hence differentiate it


A particle is moving in a straight line with simple harmonic motion. The period of the motion is (3pi/5)seconds and the amplitude is 0.4metres. Calculate the maximum speed of the particle.


Given that x = i is a solution of 2x^3 + 3x^2 = -2x + -3, find all the possible solutions


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning