mk trình bày trong hình 

$\begin{array}{l}1)\\(x-3)(x-5)(x-6)(x-10)-24x^2\\=[(x-3)(x-10][(x-5)(x-6)]-24x^2\\=(x^2 -13x +30)(x^2-11x +30) -24x^2\\=x^2[(x+\dfrac{30}{x} - 13)(x+\dfrac{30}{x} - 11) - 24]\\=x^2[(t -13)(t -11)-24] \, Với \, (t=x+\dfrac{30}{x})\\=x^2(t^2-24t+119)\\=x^2(t-7)(t-17)\\=x^2(x+\dfrac{30}{x} - 7)(x+\dfrac{30}{x}-17)\\=(x^2-7x+30)(x^2-17x+30)\\2)\\(x-1)(x+2)(x+3)(x-6)+32x^2\\=[(x-1)(x-6)][(x+2)(x+3)] + 32x^2\\=(x^2 - 7x + 6)(x^2 + 5x + 6) + 32x^2\\=x^2[(x+\dfrac{6}{x} - 7)(x + \dfrac{6}{x} + 5) + 32]\\=x^2[(t - 7)(t+5)+32]\\=x^2(t^2-2t-3)\\=x^2(t+1)(t-3)\\=x^2(x+\dfrac{6}{x}+1)(x+\dfrac{6}{x}-3)\\=(x^2+x+6)(x^2-3x+6)\\3)\\(x+1)(x-4)(x+2)(x-8)+4x^2\\=[(x+1)(x-8)][(x-4)(x+2)] + 4x^2\\=(x^2-7x-8)(x^2-2x-8)+4x^2\\=x^2[(x-\dfrac{8}{x} - 7)(x-\dfrac{8}{x} - 2) + 4]\\=x^2[(t-7)(t-2) + 4]\\=x^2(t^2 -9t + 18)\\=x^2(t-3)(t-6)\\=x^2(x-\dfrac{8}{x}-3)(x-\dfrac{8}{x}-6)\\=(x^2-3x-8)(x^2-6x-8)\\4)\\(x-2)(x-3)(x-6)(x-4)-72x^2\\=[(x-2)(x-6)][(x-3)(x-4)]-72x^2\\=(x^2 - 8x + 12)(x^2 - 7x + 12) - 72x^2\\=x^2[(x+\dfrac{12}{x}-8)(x+\dfrac{12}{x}-7)-72]\\=x^2[(t-7)(t-8)-72]\\=x^2(t^2 -15t -16)\\=x^2(t+1)(t-16)\\=x^2(x+\dfrac{12}{x} + 1)(x+\dfrac{12}{x} - 16)\\=(x^2+x+12)(x^2-16x+12)\\5)\\(x+3)(x-1)(x-5)(x+15) +64x^2\\=[(x+3)(x-5)][(x-1)(x+15)]+64x^2\\=(x^2 -2x - 15)(x^2 + 14x -15)+64x^2\\=x^2[(x-\dfrac{15}{x} -2)(x-\dfrac{15}{x}+14)+64]\\=x^2[(t-2)(t+14)+64]\\=x^2(t^2 + 12t +36)\\=x^2(t+6)^2\\=x^2(x-\dfrac{15}{x} + 6)^2\\=(x^2 + 6x - 15)^2\\6)\\(x-2)(x-4)(x-5)(x-10)-54x^2\\=[(x-2)(x-10)][(x-5)(x-4)] - 54x^2\\=(x^2 -12x + 20)(x^2 -9x + 20) - 54x^2\\=x^2[(x+\dfrac{20}{x} - 12)(x+\dfrac{20}{x} - 9) - 54]\\=x^2[(t-12)(t-9)-54]\\=x^2(t^2 - 21t +54)\\=x^2(t-3)(t-18)\\=x^2(x+\dfrac{20}{x}-3)(x+\dfrac{20}{x}-18)\\=(x^2 -3x+20)(x^2 -18x+20)\\7)\\(x+2)(x-4)(x+6)(x-12)+36x^2\\=[(x+2)(x-12)][(x-4)(x+6)] + 36x^2\\=(x^2 -10x -24)(x^2 +2x -24) + 36x^2\\=x^2[(x-\dfrac{24}{x}-10)(x-\dfrac{24}{x}+2)+36]\\=x^2[(t-10)(t+2)+36]\\=x^2(t^2 -8t +16)\\=x^2(t-4)^2\\=x^2(x-\dfrac{24}{x}-4)^2\\=(x^2 -4x - 24)^2\\8)\\4(x+5)(x+6)(x+10)(x+12)-3x^2\\=4[(x+5)(x+12)][(x+6)(x+10)] -3x^2\\=4(x^2 + 17x + 60)(x^2+17x+60)-3x^2\\=x^2[4(x+\dfrac{60}{x}+17)(x+\dfrac{60}{x}+16)-3]\\=x^2[4(t+17)(t+16)-3]\\=x^2(4t^2 +132t +1085)\\=x^2(2t+31)(2t+35)\\=x^2(2x+\dfrac{120}{x}+31)(2x+\dfrac{120}{x}+35)\\=(2x^2+31x+120)(2x^2+35x+120)\\9)\\(x+2)(x+3)(x+8)(x+12)-4x^2\\=[(x+2)(x+12)][(x+3)(x+8)]-4x^2\\=(x^2+14x+24)(x^2+11x+24)-4x^2\\=x^2[(x+\dfrac{24}{x}+14)(x+\dfrac{24}{x}+11)-4]\\=x^2[(t+14)(t+11)-4]\\=x^2(t^2 + 25t + 150)\\=x^2(t+15)(t+10)\\=x^2(x+\dfrac{24}{x} +15)(x+\dfrac{24}{x}+10)\\=(x^2 + 15x + 24)(x^2+10x+24)\\10)\\(x-18)(x-7)(x+35)(x+90)-67x^2\\=[(x-18)(x+35)][(x-7)(x+90)]-67x^2\\=(x^2 +17x -630)(x^2+83x-630)-67x^2\\=x^2[(x-\dfrac{630}{x}+17)(x-\dfrac{630}{x}+83)-67]\\=x^2[(t+17)(t+83)-67]\\=x^2(t^2 +100t +1344\\=x^2(t+84)(t+16)\\=x^2(x-\dfrac{630}{x}+84)(x-\dfrac{630}{x}+16)\\=(x^2+84x-630)(x^2+16x-630)\end{array}$