factoring out x from the first column makes a nice 1 in the bottom left
Then doing R2 <- R2 - (x-1)/x R3 yields
((x-2)/x (x-1)² x^3)
(0 x² - (x-1)(x+1)²/x (x+1)^3 - (x-1)(x+2)^3/x)
(1 (x+1)² (x+2)^3)
Then R3 <- R3 - x/(x-2) R1 yields
((x-2)/x (x-1)² x^3)
(0 x² - (x-1)(x+1)²/x (x+1)^3 - (x-1)(x+2)^3/x)
(0 (x+1)² - x(x-1)²/(x-2) (x+2)^3 - x^4/(x-2))
Now C2 <- C2 - ( (x+1)² - x(x-1)²/(x-2)) / (x+2)^3 finally yields, after multiplying back C1 by x
((x-2) (x-1)² - x^3( (x+1)² - x(x-1)²/(x-2)) / (x+2)^3 x^3)
(0 x² - (x-1)(x+1)²/x - ((x+1)^3 - (x-1)(x+2)^3/x) * ((x+1)² - x(x-1)²/(x-2)) / (x+2)^3) (x+1)^3 - (x-1)(x+2)^3/x)
(0 0 (x+2)^3 - x^4/(x-2))
Hence the determinant is
(x-2) * ((x+2)^3 - x^4 / (x-2)) * (x² - (x-1)(x+1)²/x - ( (x+1)^3 - (x-1)(x+2)^3/x) * ( (x+1)² - x(x-1)²/(x-2)) / (x+2)^3)
= ((x²-4)(x+2)² - x^4) * (x² - (x^3 +2x²+1 - x²-2x-1)/x - (x^3+3x²+3x+1 - ((x-1)(x^3+2x²+4x+8)/x) * (x²+2x+1) - x(x²-2x+1)/(x-2)) / (x+2)^3
etc
Or don't be an idiot like me



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