續多項式的問題II

樓上朋友的答案不對!
　(x²-x+2)(x²+x-2) - (x-2)²
= [(x²)-(x-2)][(x²+(x-2)] - (x-2)²
= [(x²)² - (x-2)²] - (x-2)²
= x^4 - 2 (x-2)²
= x^4 - 2x² + 8x - 8

=(X^2+X+2)(X^2+X-2)-(X-2)(X-2)
=(X^4)+(X^3)-(2X^2)+(X^3)+(X^2)-(2X)+(2X^2)+(2X)-4
=X^4+2X^3+X^2-4