(a) If the sum of the roots of the quadratic equation ky2−11y+(k−23)=0 is ‌

13

21

more than the product of the roots, then find the value of k.
OR
(b) If x=−2 is the common solution of quadratic equations ax2+x−3a=0 and x2+bx+b=0, then find the value of a2b.