Đáp án + Giải thích các bước giải:
`a)` `(6x+1)^2+(6x-1)^2-2(1+6x)(6x-1)`
`=(6x+1)^2-2(6x+1)(6x-1)+(6x-1)^2`
`=[(6x+1)-(6x+1)]^2`
`=(6x+1-6x-1)^2=0`
`b)` `3(2^2+1)(2^4+1)(2^8+1)(2^16+1)`
`=(2^2-1)(2^2+1)(2^4+1)(2^8+1)(2^16+1)`
`=(2^4-1)(2^4+1)(2^8+1)(2^16+1)`
`=(2^8-1)(2^8+1)(2^16+1)`
`=(2^16-1)(2^16+1)=2^32-1`
`c)` `x(2x^2-3)-x^2(5x+3)+3x^2`
`=2x^3-3x-5x^3-3x^2+3x^2`
`=-3x^3-3x`
`=-3x(x^2+1)`
`d)` `3x(x-2)-5x(1-x)-8(x^2-3)`
`=3x^2-6x-5x+5x^2-8x^2+24`
`=-11x+24`
`e)` Sửa đề :
`(x+8)^2-2(x+8)(x-2)+(x-2)^2`
`=[(x+8)-(x-2)]^2`
`=(x+8-x+2)^2=10^2=100`
`g)` `(x-2)^3-(x+2)(x^2-2x+4)-(x+1)(x-1)-x(2x+12)`
`=x^3-6x^2+12x-8-(x^3+8)-(x^2-1)-2x^2-12x`
`=x^3-6x^2+12x-8-x^3-8-x^2+1-2x^2-12x`
`=-9x^2-15`
