Factorise and solve x^2 – 8x + 15 = 0

MYTUTOR SUBJECT ANSWERS

Answers / Maths / GCSE / Factorise and solve x^2 – 8x + 15 = 0

607 views

Factorise and solve x^2 – 8x + 15 = 0

This equation is of the form ax² + bx + c = 0 (where a = 1, b = -8 and c = 15). To help solve it, find two numbers that add to give the value of b (the 'sum') and also when multiplied together give the same answer as a*c (the 'product').

For this equation, the sum = -8 and the product = 15.

Because the sum is negative and the product is positive we're looking for two negative numbers.

In this case they are -3 and -5, so the factorised equation would be: (x - 3)(x - 5) = 0.

In the factorised equation, the two bracket terms are multiplied together, so to solve the equation, make one of the brackets equal zero.

The two 'roots' of the equation, i.e. the values of x that make the equation true, are x = 3 and x = 5.

Andrew B. GCSE Chemistry tutor, A Level Chemistry tutor, GCSE Maths t...

1 year ago

Answered by Andrew, who tutored GCSE Maths with MyTutor

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

662 SUBJECT SPECIALISTS

Guido B. 11 Plus Maths tutor, GCSE Maths tutor, 13 Plus Maths tutor,...

View profile

£18 /hr

Guido B.

Degree: Aeronautical Engineering (Masters) - Imperial College London University

Subjects offered:Maths, Science+ 3 more

“Expert tuition from an expert. A second year Uni student who's completed the hassle of GCSEs and A Levels, and can teach you the easy way to pass and succeed!”

4.5

4 reviews | 3 completed tutorials

Save profile

Piyush S. A Level Maths tutor, IB Maths tutor, 11 Plus Maths tutor, 1...

View profile

£30 /hr

Piyush S.

Degree: Electronics Engineering (Doctorate) - Imperial College London University

Subjects offered:Maths

“I am an experienced and passionate tutor for Maths and Science (Physics in particular). Throughout my higher education, I have been wondering about how Mathematics acts as a tool to model and simplify the complicated concepts of the P...”

4.9