Đáp án:

 

Giải thích các bước giải:

 `A=(2x-1)^2 +3x(x+2) - (x-1)(x+1)`

`A=4x^2 - 4x +1 +3x^2 + 6x - x^2 +1`

`A=(4x^2 + 3x^2 - x^2) + (-4x+ 6x) + (1+1)`

`A=6x^2 + 2x +2`

`B=(2x-3y)^2 + 5(xy -1) - (x-y)(x+y)`

`B=4x^2 - 12xy + 9y^2 + 5xy - 5 - x^2 +y^2`

`B=(4x^2 -x^2) + (-12xy + 5xy) + (9y^2 + y^2)`

`B=3x^2 - 7xy + 10y^2`

`C=4x(x+1)^2 +3(x-3)(2-3x)`

`C=4x(x^2 +2x+1) +3(-3x^2 +11x-6)`

`C=4x^3 + 8x^2 +4x - 3x^2 +33x - 18`

`C=4x^3 + (8x^2 - 3x^2) + (4x +33x) -18`

`C=4x^3 + 5x^3 + 37x -18`

`D=8x(x-1)(x+2)-(2x-1)(4x^2 +2x+1)`

`D=8x(x^2 +x -2) -(8x^3-1)`

`D=8x^3 + 8x^2 - 16x - 8x^3 +1`

`D=(8x^3 -8x^3) + 8x^2 -16x +1`

`D=8x^2 - 16x+1`

`E=3(5x-2)^2 +5(3-2x)(x+1)-3x(x-2)`

`E=3(25x^2 - 20x +4) +5(-2x^2+x+3) - 3x^2 + 6x`

`E=75x^2 -60x +12 - 10x^2 +5x +15-3x^2+6x`

`E=(75x^2 -10x^2 -3x^2) + (-60x+ 5x + 6x) + (12+15)`

`E=62x^2 - 49x+27`