Solve |3x+1| = 1

Firstly square both sides. This way, we now know that both sides have to be positive

(3x+1)^2 = 1

(3x+1)(3x+1) = 1

Expand the quadratic...

9x^2 + 12x + 4 = 1

9x^2 + 12x + 3 = 0

Now complete the square. Firstly divide everything by 12 to make this simpler

x^2 + (4/3)x + 1/3 = 0

(x + (2/3))^2 -4/9 + 1/3 = 0

(x + (2/3))^2 = 1/9

Square root both sides, be sure to have give the negative value on RHS too

x+(2/3)=+-(1/3)

x=-1/3 x=-1

Answered by Dorothy T. Maths tutor

6467 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

A particle of mass m is placed on an slope with an incline 30 degrees. Once released it accelerates down the line of greatest slope at 2 m s^-2. What is the coefficient of friction between the particle and the slope?


How do I show two vectors are perpendicular?


The height (h) of water flowing out of a tank decreases at a rate proportional to the square root of the height of water still in the tank. If h=9 at t=0 and h=4 at t=5, what is the water’s height at t=15? What is the physical interpretation of this?


Show that cosec(2x) + cot(2x) = cot(x)


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences