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

Answered by Molly I. Maths tutor

6027 Views

See similar Maths A Level tutors

Related Maths A Level answers

All answers ▸

integrate (4cos^4 x -4cos^2x+1)^1/2


Is the trapezium rule an exact method of integration?


Differentiate y = 5x^3 + 7x + 3 with respect to x


Given y=rootx + 4/rootx = 4, find the value of dy/dx when x=8, writing your answer in the form aroot2, where a is a rational number.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences