Factorise the quadratic equation: x^2 + 5x + 6 = 0 and hence find the two solutions to the equation.

  1. Start by writing the equation out again: x2 + 5x + 6 = 0

  2. I do it by thinking which two numbers add together to = 5 and which same two numbers multiply to = 6. The answer to this is 2 and 3.

  3. So the next step is to write the eqaution down in factorised form (there is no need to do any other thinking about the numbers to go inside the brackets becuase the coefficient of x2 is 1).

  4. So we now have: (x + 2)(x + 3) = 0 - This is the answer to the first part of the question.

  5. To get the answer to the second part, one of the two brackets must = 0 (because if two numbers multiplied together = 0, one number must = 0).

  6. So either x + 2 = 0, in which case x = -2, or x + 3 = 0 in which case x = -3. This is the answer to the second part.

7.To check, substitute these number back into the original equation: (-2)2 + 5(-2) + 6 = 4 - 10 + 6 = 0 (correct) (-3)2 + 5(-3) + 6 = 9 - 15 + 6 = 0 (correct)

Answered by Callum J. Maths tutor

6885 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Write 2x^2 + 6x + 6 in the form a(x^2 + b) + c by completing the square.


Find the values of a, b and c in the equation: (5x + 3)(ax + b) = 10x^2 + 11x + c.


How do I 'simplify' a surd?


Factorise 4x+6x^2


We're here to help

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