If p and q are the roots of the equation x2 +bx+c then:
p+q=(-b)/a = -(-(k+6))/1
p*q=c/a = 2(2k-1)/1
According to the information: p+q=1/2(p*q)
k+6=(1/2) *(2*( 2k-1))
solve it and see that it comes to…..
k+5=2k-1 [subtract both sides by k]
HOPE YOU UNDERSTOOD,GOOD LUCK!!!