Đáp án`+`Giải thích các bước giải:

`a)(x-2)(x+2)-(x-3)(x+1)`

`=x^2 - 4 - (x^2 + x -3x - 3)`

`=x^2 - 4 - x^2 + 2x + 3`

`=2x-1 `

`b)(3x-5)^2 - 2(3x-5)(3x+5)+(3x+5)^2`

`=(3x-5-3x-5)^2`

`=10^2`

`=100^2`

`a)(x+4)^2+(x+5)(x-5)-2x(x+1)`

`=x^2+8x+16+x^2-25-2x^2-2x`

`=(x^2+x^2-2x^2)+(8x-2x)+(16-25)`

`=6x-9`

`b)(x+2)^3+(x-3)^2-x^2(x+5)`

`=x^3+6x^2+12x+8+x^2-6x+9-x^3-5x^2`

`=(x^3-x^3)+(6x^2+x^2-5x^2)+(12x-6x)+(8+9)`

`=2x^2+6x+17`