國二數學 因式分解,如圖片?

[(x-1)(x-6)][(x-2)(x-3)] - 3x^2

= [(x^2+6)-7x][(x^2+6)-5x] - 3x^2

= (x^2+6)^2 - 12x(x^2+6) + 35x^2 - 3x^2

= (x^2+6)^2 - 12x(x^2+6) + 32x^2

= [(x^2+6) - 4x][(x^2+6)-8x]

= (x^2-4x+6)(x^2-8x+6)

= (x^2-4x+6)(x^2-8x+16-10)

= (x^2-4x+6)[(x-4)^2-10]

= (x^2-4x+6)(x-4+√10)(x-4-√10)