Question

x^2+1/x=7; find x-1/x , x+1/x , 3x^2-3/x^2

Answer 1

x^2+1/x=7
7x=x^2
7=x
7-1/7=48/7
7+1/7=50/7
21^2-6/49
441-6/49
441×49-6/49