Factorise and solve the quadratic : 3x^2 + 15x +18 = 0

First we look to see if there is a common factor in the equation. In this case there is a common factor of 3, therefore we can take 3 out as a factor. 3(x2 +5x +6) = 0
The inside of the bracket is now a standard recognisable quadratic which is simple to factorise. Remember to factorise a quadratic, it is split into two brackets (x+A)(x+B), where A and B are integers. A and B here must add together to make 5, and multiply together to make 6. In this example you can see that A is 2 and B is 3. (or vice versa, it doesn't matter). For the equation to be true then either (x+3)=0 or (x+2)=0 because the factor of 3 on the outside of the bracket cannot equal 0. So the solution is x= -3 or x= -2.

Answered by Holly W. Maths tutor

3611 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Anna and Lionel share $675 in the ratio 4 : 5 Lionel gives 3 5 of his share of the money to his mother. How much money does Lionel give to his mother?


Calculate 64^2/3. (No calculator)


Expand and simplify (2x+4)(x+2)


Solve the inequality 2x - 10 < 6 - 2x


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 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences