Factorise x^3+3x^2-x-3

Test factors of -3 to find a root for the equation. For example, try 1, 1^3+3*1^2-1-3=0, so 1 is a root, and (x-1) is a factor. Now it's known that: (ax^2+bx+c)(x-1)=x^3+3x^2-x-3. By comparing coefficients for x^3 term, a=1, and for x^0 term, c=3. Then for the x term, c-b=-1, so b=4. Therefore the original equation equals (x^2+4x+3)(x-1). Now factorise the quadratic to give (x+3)(x+1)(x-1). Expanding the bracket again can be used to check your answer.

Answered by Sian C. Maths tutor

6299 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Differentiate sin(x)*x^2


Express cos(2x) in the form acos^2(x) + b, where a and b are constants.


Express 9^(3x+1) in the form 3^y, giving "y" in the form "ax+b" where "a" and "b" are constants.


How do I work out (2+y)^4 using the binomial expansion?


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