How would you solve a quadratic equation by factorising?

MYTUTOR SUBJECT ANSWERS

Answers / Maths / GCSE / How would you solve a quadratic equation by factorising?

572 views

How would you solve a quadratic equation by factorising?

Solve the equation : x² - 8x + 15

The first step is to factorise the quadratic equation.

1. You must find two numbers which will add to give -8 and multiply to give 15.

The numbers that would do this are -5 and -3.

Therefore (x-5) (x-3). To check whether this is correct, you can expand the brackets and it should give you the equation you first started with.

The second step is to find the value of x.

2. For this you must equate each bracket to 0.

(x-5)= 0 and (x-3)=0

Now solve : x = 5 and x= 3

The third step is subsitution

3. Finally to check this is correct. Substitute the values of x into the equation.

x² - 8x + 15

-Subsitute x =5

5²-8 x 5 +15 = 0

25-40+15 = 0

-Subsitute x=3

3²- 8 x 3 +15 = 0

9-24+15=0

These 3 simple steps will help you solve any quadratic equation.

Angelin G. GCSE Maths tutor, GCSE Biology tutor, 13 plus Maths tutor...

1 year ago

Answered by Angelin, who has applied to tutor GCSE Maths with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist

533 SUBJECT SPECIALISTS

Ayusha A. A Level Maths tutor, GCSE Maths tutor, A Level Physics tuto...

View profile

£22 /hr

Ayusha A.

Degree: BEng electrical and electronics engineering (Bachelors) - Newcastle University

Subjects offered:Maths, Physics+ 1 more

“About me: I am a final year Electrical and Electronic Engineering student at Newcastle University. I took Mathematics, Further Mathematics, Chemistry and Physics as my A-level subjects. I did peer mentoring in university and also have...”

5.0

41 reviews | 103 completed tutorials

Save profile

Victoria S. GCSE Biology tutor, A Level Biology tutor, GCSE Maths tutor

View profile

£24 /hr

Victoria S.

Degree: Physiology (Bachelors) - Liverpool University

Subjects offered:Maths, Biology

“Here to help with last minute revision prep! I'm Tory, in my final year studying Physiology at Uni of Liverpool and am a 5* rated tutor here to suit your needs.”

5.0

102 reviews | 85 completed tutorials

Save profile

£36 /hr

William A.

Degree: Law (Bachelors) - Cambridge alumni University

Subjects offered:Maths, Law+ 3 more

“I recently graduated from the University of Cambridge in Law and completed my A Levels in 2012 with 4 A*s in Maths, Economics, Physics and Chemistry.I am a friendly and approachable person and have previously tutored A Level Econom...”

5.0