Find the roots of x^2-9=0

Stage 1: Identify that the equation is a quadratic and that the question is asking you to find out which values 'x' fit this equation. Quadratics can be written algebraically in the form ax2+bx+c and have 0, 1 or 2 roots.Stage 2: Notice that the 'b' value is 0 and the 'c' value is a square number. This suggests that the equation can be solved by using the 'Difference of Two Squares'Stage 3: Identify that the root of 9 is 3, and so using the difference of two squares, the equation can be factorised to (x-3)(x+3)=0Stage 4: Solve the newly factorised equation for the two roots of x=3 and x=-3

JD
Answered by Jamie D. Maths tutor

2587 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

How to determine the number of unique real roots of a quadratic equation.


Solve algebraically the simultaneous equations x^2 + y^2 = 25 and y - 3x = 13


Expand and simplify (3a+b)(a-2b).


What is the best way to solve simultaneous equations?


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