MYTUTOR SUBJECT ANSWERS

270 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...

6 months ago

Answered by Michael, an A Level Maths tutor with MyTutor


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

265 SUBJECT SPECIALISTS

£20 /hr

Sam A.

Degree: Mathematics (Bachelors) - York University

Subjects offered:Maths, Further Mathematics + 1 more

Maths
Further Mathematics
Biology

“An enthusiastic and engaging undergrad mathematician (University of York, MMath), whose lessons are focused for the student, and never the teacher.”

£20 /hr

Elliot D.

Degree: Mathematics (Bachelors) - St. Andrews University

Subjects offered:Maths, Physics

Maths
Physics

“Hi, I'm a 2nd year Computer Science student at St Andrews University. I mainly teach Maths at both GCSE and A-level.”

£20 /hr

Raghav A.

Degree: Chemical Engineering (Masters) - Bath University

Subjects offered:Maths, Physics+ 2 more

Maths
Physics
Chemistry
-Personal Statements-

“If you are looking for a tutor who is not only approachable and passionate about his subjects, but willing to go the extra mile, I am here to help”

About the author

Michael W.

Currently unavailable: for new students

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...”

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

Find f''(x), Given that f(x)=5x^3 - 6x^(4/3) + 2x - 3

Differentiate xcos(x) with respect to x

Integrate the function : F'(x)=3x^2+4x-5

How can I derive an equation to find the sum of an arithmetic sequence?

View A Level Maths tutors

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

mtw:mercury1:status:ok