MYTUTOR SUBJECT ANSWERS

51 views

Find the factors of x^3−7x−6

To find the factors of x3-7x-6, a method called equating coefficients can be used.

Firstly, set the equation to zero and find a suitable number which satisfies the equation, in this case x=-1 satisfies the equation, therefore one factor is (x+1), therefore the cubic equation can be represented by:

(x+1)(Ax2+Bx+C)

Expanding this polynomial gives:

x(Ax2+Bx+C)+(Ax2+Bx+C)

Ax3+Bx2+Cx+Ax2+Bx+C

Ax3+(A+B)x2+(C+B)x+C

Equating the coefficients looks at the number before the variable and comparing it with the predicted equation.

Ax3=1x................................(1)

(A+B)x2=0x2...........................(2)

(C+B)x=-7x ............................(3)

C=-6 ......................................(4)

therefore A=1, C=-6, and B=-1

(x-1)(x2-x-6)

and this is a matter of factorising (x2-x-6) which is (x-3)(x-2)

and so the factorised form becomes:

(x-1)(x-3)(x-2)

Michael W. GCSE Maths tutor, IB Maths tutor, A Level Maths tutor, GCS...

1 month ago

Answered by Michael, an A Level Maths tutor with MyTutor

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

186 SUBJECT SPECIALISTS

£26 /hr

George B.

Degree: Mathematics (Masters) - Warwick University

Subjects offered: Maths, Further Mathematics + 1 more

Maths
Further Mathematics
.STEP.

“Third year undergraduate at one of the top universities for Maths. Eager to tutor and help improve your grades.”

£20 /hr

George I.

Degree: Electrical and Electronic Engineering (Masters) - Bristol University

Subjects offered: Maths, Further Mathematics

Maths
Further Mathematics

“About Me: I am currently a third year Electrical and Electronic engineering undergraduate at the University of Bristol. I have always enjoyed taking mathematics and further mathematics as I look forward to tackling problems with nume...”

MyTutor guarantee

£24 /hr

Osian S.

Degree: Mathematics (Masters) - Warwick University

Subjects offered: Maths, Further Mathematics

Maths
Further Mathematics

“Hi, I'm Osian, a Master's student at the University of Warwick. I've had fun with mathematics from a young age, and I hope to be able to instill this passion for mathematics in you, through my tutorials! Throughout my time at Warwick,...”

About the author

Michael W.

Currently unavailable: until 16/12/2016

Degree: Aerospace Engineering (Masters) - Bristol University

Subjects offered: Maths, Science+ 2 more

Maths
Science
Physics
Chemistry

“I am a fourth year aerospace engineering student at the University of Bristol. I have a passion for science and mathematics as it can be applied to almost everything and enables us to solve challenging problems! I hope to share my kno...”

MyTutor guarantee

You may also like...

Posts by Michael

Explain how fluorescent tubes work

Find the coordinates that correspond to the maximum point of the following equation: y = −16x^2 + 160x - 256

Find the factors of x^3−7x−6

What four factors influence the rate of reaction?

Other A Level Maths questions

What is a derivative?

The polynomial x^3 - 2*x + a, where x is a constant is denoted by p(x). It is given that x+2 is a factor of p(x). Find a

What is the derivative of x^x

∫(1 + 3√x + 5x)dx

View A Level Maths tutors

Cookies:

We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss

mtw:mercury1:status:ok