Đáp án:
Câu a) do đề sai nên không thể phân tích được.
Giải thích các bước giải:
`b)(x-3)(x-5)(x-6)(x-10)`
`=[(x-3)(x-10)][(x-5)(x-6)]`
`=(x^2-13x+30)(x^2-11x+30)`
`=(x^2-12x+30-x)(x^2-12x+30+x)-24x^2`
`=(x^2-12x+30)^2-x^2-24x^2`
`=(x^2-12x+30)^2-25x^2`
`=(x^2-12x+30)^2-(5x)^2`
`=(x^2-12x+30-5x)(x^2-12x+30+5x)`
`=(x^2-17x+30)(x^2-7x+30)`
`=(x^2-2x-15x+30)(x^2-7x+30)`
`=[x(x-2)-15(x-2)](x^2-7x+30)`
`=(x-2)(x-15)(x^2-7x+30)`
`c)(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+6x-15-8x)(x^2+8x-15+6x)-64x^2`
`=(x^2+6x-15)^2-(8x)^2+64x^2`
`=(x^2+6x-15)^2-64x^2+64x^2`
`=(x^2+6x-15)^2`
