The quadratic equation 2x^2 + 8x + 1 = 0 has roots a and b. Write down the value of a + b, a*b and a^2 + b^2.

Using Vieta's formulas, which make the correspondence between the sums and products of the roots of a polynomial and its coefficients, we can deduce that a + b = (-8)/2 = -4, a*b = 1/2 =0.5 and a^2 + b^2 = (a+b)^2 - 2*ab = (-4)^2 - 2*0.5 = 16 - 1 = 15. 

Andreea I. Uni Admissions Test .MAT. tutor, Uni Admissions Test .STEP...

12 months ago

Answered by Andreea, an A Level Maths tutor with MyTutor

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


£20 /hr

Seb G.

Degree: Mathematics (Masters) - Bath University

Subjects offered:Maths


“Me: I'm a second year maths student at the University of Bath. I fell in love with maths after a rocky start with the subject, so believe that I can help people regardless of whether they like maths or not.  I've been tutoring maths l...”

MyTutor guarantee

£20 /hr

Matt M.

Degree: Mathematics (Masters) - Bristol University

Subjects offered:Maths, Physics+ 1 more

Further Mathematics

“Hi! My name's Matt and I'm a first year Maths student at the University of Bristol. I love Maths, especially when I can help other people to understand it.”

MyTutor guarantee

£24 /hr

Emma H.

Degree: Earth Sciences (Masters) - Oxford, Exeter College University

Subjects offered:Maths, Science+ 3 more


“Hi, I'm Emma. I'm a second year Earth Science student at The University of Oxford and i love all things Maths and Science! I've been tutoring for over three years one to one for both GCSE and A Level and I love helping people achieve ...”

About the author

£20 /hr

Andreea I.

Degree: Mathematics and Computer Science (Masters) - Oxford, Merton College University

Subjects offered:Maths, .STEP.+ 1 more


“Top tutor from the renowned Russell university group, ready to help you improve your grades.”

MyTutor guarantee

You may also like...

Posts by Andreea

By use of calculus, show that x − ln(1 + x) is positive for all positive x.

How many distinct real roots does the equation x^3 − 30x^2 + 108x − 104 = 0 have?

The quadratic equation 2x^2 + 8x + 1 = 0 has roots a and b. Write down the value of a + b, a*b and a^2 + b^2.

Other A Level Maths questions

Differentiate ((x^2)+1)^2

How do you find the normal to a curve at a given co-ordinate?

If f'(x)=3x(x - 1), find f(x)

Find the stationary points of the function y = (1/3)x^3 + (1/2)x^2 - 6x + 15

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