Rut gon: a) (2x+3)^2-(x-5)^2-(x-1) (3x+2) b) 5x (x-6)-(3x+4 (3x-4)- 6x^2 c) (2x-4)^2-5x(2x+1)-(4x+1)^2

Đáp án:

Giải thích các bước giải:

 `a) (2x+3)^2-(x-5)^2-(x-1) (3x+2)`

`=4x^2+12x+9-(x^2-10x+25)-(3x^2+2x-3x-2)`

`=23x-11`

`b) 5x (x-6)-(3x+4) (3x-4)- 6x^2 `

`=5x^2-30x-9x^2+16-6x^2`

`=-10x^2-30x+16`

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

`=4x^2-16x+16-(10x^2+5x)-(16x^2+8x+1)`

`=-22x^2-29x+15`