Find all three roots of the cubic: 2x^3 +5x^2 - 22x +15=0.

First try a trivial solution, x=0: doesn't work. Then try x=1 this does work so (x-1) is a factor of the cubic. Through algebraic factorisation (2x2+7x-15) comes out as a factor. This can be factorised into (2x-3)(x+5) leaving x=1, x=3/2 and x=-5 as the three solutions.

SW
Answered by Stanley W. Maths tutor

3596 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Write x^2 + 8x + 7 in the form (x + a)^2 + b


Solve the simultaneous equations. 2x + y = 18, x − y = 6


Bob lives 2km away from Alice and the school is 1km away from Bob. Alice sets off to meet Bob at 8am and she meets him at 8:15 and they carry on walking at the same pace. School starts at 8:20. Do they get to school on time? How early/late are they?


Claire drove from Manchester to London, it took her 4 hours at an average speed of 85 km/h. Matt drove from Manchester to London, it took him 5 hours. Assuming he took the same route as Claire and took no breaks, work out his average speed in km/h.


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