SOLUTION: Q. Obtain the values of k such that x^2-6x+k=0 has real roots. is it to solve by making b^2-4ac=0 i got the answer as k=9 also Calculate the value of if the diff

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Q. Obtain the values of k such that x^2-6x+k=0 has real roots. is it to solve by making b^2-4ac=0 i got the answer as k=9 also Calculate the value of if the diff      Log On


   

Question 569421: Q. Obtain the values of k such that x^2-6x+k=0 has real roots.
is it to solve by making b^2-4ac=0
i got the answer as
k=9
also
Calculate the value of if the difference between the roots of x^2-6x+k=0 is 3
i got the answer as k=27/4
please can u help me to varify my answers.. i will be happy to forward u the steps which i prepared in word. to ur email.
Thanks
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
b^2 - 4ac only has to be greater than or equal to 0, not necessarily equal to 0, so check the first problem.

For the second one, the roots are



For the roots to differ by 3, you'll need the sqrt(36-4k) to equal 3. This is because +3/2, -3/2 differ by 3 (you'll get something like 9/2, 3/2). So we have

, k = 27/4, correct.