Question

Is P ={x:x belongsto N , x square -x-2=0} a null set? justify your answer.

Answer 1

x^2-x-2=0 =>x^2-2x+1x-2=0 =>(x^2-2x)+(1x-2)=0 =>x(x-2)+1(x-2)=0 =>(x-2)(x+1)=0 either (x-2)=0 or (x+1)=0 (x-2)=0 =>x=2 (x+1)=0 => x=(-1) which is not possible. So X=2 is ur answer