Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta

How do you know which method to use to solve quadratic equations? watch

    • Thread Starter

    how do you know whether to factorise it, complete the square, use the quadratic formulae ect?

    (Original post by Bertybassett)
    how do you know whether to factorise it, complete the square, use the quadratic formulae ect?
    You can use any method unless the question specifies otherwise.
    Always factorise if you can. It is likely to be the most efficient method. Make sure you have a method to factorise trickier problems where the coefficient of x squared is greater than 1.
    If it doesn't factorise or you can't see how it does or you are told the solutions will be in some kind of surd form or it says "exact solutions" then you can use either the formula or completing the square. They are effectively the same thing. Most people find it easier and more efficient to memorise the formula than follow the completed square process.
    Some questions will ask you to write a quadratic in completed square format. They may then say "hence solve" in which case they want you use the completed square or the may say "hence or otherwise" in which case it's up to you.
    On a calculator exam if you are told to give your answer to "3 significant figures" this tells you it doesn't factorise and the formula is probably the best approach.

    Posted from TSR Mobile
Do you agree with the proposed ban on plastic straws and cotton buds?
Help with your A-levels

All the essentials

The adventure begins mug

Student life: what to expect

What it's really like going to uni


Essay expert

Learn to write like a pro with our ultimate essay guide.

Uni match

Uni match

Our tool will help you find the perfect course for you

Study planner

Create a study plan

Get your head around what you need to do and when with the study planner tool.

Study planner

Resources by subject

Everything from mind maps to class notes.

Hands typing

Degrees without fees

Discover more about degree-level apprenticeships.

A student doing homework

Study tips from A* students

Students who got top grades in their A-levels share their secrets

Study help links and info

Can you help? Study help unanswered threadsRules and posting guidelines

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.