Solve for x when |x-1|<|2x+3|

A graph is always helpful when dealing with this kind of problems. The first thing to do when sketching is to find the intersection with the axis. Ignore the modulus function for the moment. Then flip what's under x axis to include the modulus function. For |x-1| to be less than |2x+3|, its graph needs to be under the other function. We can see from the graph which section that is.The next step is to work out the intersection of two functions. If a section of the function is flipped, it means the sign has been changed, i.e. x-1 becomes 1-x. The first intersection can be found by solving 1-x=-2x-3, since they are both flipped. The second one can be found by solving 1-x=2x+3. They give x=-4 and x=-2/3. From the graph, it can be seem that x needs to have a range of x<-4 or x>-2/3.

Answered by Qinyu Z. Maths tutor

3233 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Differentiate the expression x^6+5x^4+3 with respect to x


Express 3sinx - 2cosx in the form R(sin(x-a) given R>0 and 0<a<90°. Hence solve 3sinx - 2cosx = 1 in the interval 0<x<360°. What are the maximum and minimum values of 2sinx - 3cosx?


Express (x+1)/2x + (2x+3)/(x+1) as one term


Differentiate y=x(e^x)


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences