Question

a²-4a-1=0 find the value of a²-1/a²​

Answer 1

Answer:

18

Step-by-step explanation:

a²-4a=1 is dividing by a

a-4=1/a

a-1/a=4

on squaring on both sides

a²-2+1/a²=4²

a²-2+1/a²=16

a²+1/a² = 16+2

= 18