दिया गया समीकरण
12x4 – 56x3 + 89x2 – 56x + 12 = 0
दोनों पक्षों में x2 से भाग करने पर,

x2 + 1/x2 + 2 = y2
x2 + 1/x2 = y2 – 2
समीकरण (1) में x2 + 1/x2 = y2 – 2 तथा x + 1/x = y
12(y2 – 2) – 56y + 89 = 0
12y2 – 24 – 56y + 89 = 0
12y2 – 56y + 65 = 0

2(x2 + 1) = 5x
2x2 – 5x + 2 = 0
2x2 – x – 4x + 2 = 0
x(2x – 1) – 2(2x – 1) = 0
(x – 2)(2x – 1) = 0

6(x2 + 1) = 13x
6x2 – 13x + 6 = 0
6x2 – 9x – 4x + 6 = 0
3x(2x – 3) – 2(2x – 3) = 0
(3x – 2)(2x – 3) = 0
x = 2/3 , 3/2