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.

  • Google+ icon
  • LinkedIn icon
  • 732 views

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...

About the author

is an online A Level Maths tutor with MyTutor studying at Oxford, Merton College University

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

95% of our customers rate us

Browse 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