the roots of x^3-6x^2-13x-k=0 form an arethmatic sequence
a) What is the median term of the arethematic sequence
b) Find the value of k
Let the sequence be a-d, a, a+d
So
\(x^3-6x^2-13x-k=(x-(a-d))\;x\;(x-(a+d))\\ x^3-6x^2-13x-k=x\;((x-a)+d))\;(x-a)-d))\\ x^3-6x^2-13x-k=x\;((x-a)^2-d^2)\\ etc\)
Simplify it down and equaet coefficients.
+62 
