Concept: The general form of quadratic equation: ax2+bx+c=0 The discriminant of the equation is D=b2−4ac - D>0, roots are unequal and real - D<0, roots are imaginary - D=0, roots are real and equal Calculation: Given : x2+2x+k=0 On comparing with general form a=1,b=2,c=k Roots are real D≥0 b2−4ac≥0 22−4×1×k≥0 4−4k≥0 4≥4k 1≥k k≤1