If sum of squares of the roots of the equation x^2+k x-b=0 is 2 b , what is k equal to?

Step-by-step solution

Let , be two roots then array rlrl & & ^2+ ₂ & =2 b (given) Now & & + & =- k 1 =-k & & & = -b 1 =-b & & ^2+ ^2 & =( + )^2-2 & & 2 b & =k^2-2(-b) & & 2 b & =k^2+2 b & k^2 & =0 k=0 . array