Question

if x² - 8x - 1 = 0, then x² + 1/x² = ?

Answer 1

x² -8x - 1 =0

x² = 8x + 1

1/x² = 1/(8x + 1)

now,

x² + 1/x² = (8x +1) + 1/(8x + 1)
= (64x² +16x + 2)/(8x +1)
={64(8x + 1) +2(8x +1)}/(8x +1)
={66(8x + 1) }/(8x + 1)
=66

Answer 2

see attachment....hope it helps...