The quadratic equation (k+1)x^2 + (5k - 3)x + 3k = 0 has equal roots. Find the possible values of k

We know the discriminant (b^2 - 4ac) must be equal to zero for an equation to have equal roots (think about the fact that the square root of this is taken in the quadratic equation). So we can form the equation (5k-3)^2 - 4(k+1)(3k) = 0Simplifying this to 13k^2 - 42k + 9 = 0 and factorising to (13k - 3)(k - 3) = 0 (easily done by spotting that 13 is prime), we can see that k = 3 or k = 3/13

MI
Answered by Molly I. Maths tutor

6675 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

Solve x^3+2x^2+x=0


Two points have coordinates (1,-6) and (-2,3). Find the equation of the line which joins them, and their midpoint.


Find the exact solution of the following equation: e^(4x-3) = 11


In the triangle ABC, AB = 16 cm, AC = 13 cm, angle ABC = 50 and angle BCA= x Find the two possible values for x, giving your answers to one decimal place.


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning