a)(x + 1)² – (x – 2)²

= (x+1-x+2)(x+1+x-2)

= 3(2x-1)

b)(x – 3)(x – 1) – (2x – 1)²

= x²-4x+3-4x²+4x-1

= -(3x²-2)

c)(x + 3)² - 2(x + 3)(1 – x) + (1 - x)²

= [(x+3)-(1-x)]²

=(2x-2)²=4(x-1)²

\(a/4x\left(x-3\right)-3x\left(2+x\right)\\ =4x.x-4x.3-3x.2-3x.x\\ =4x^2-12x-6x-3x^2\\ =x^2-18x\\ b/2x\left(5x+2\right)+\left(2x-3\right)\left(3x-1\right)\\ =2x.5x+2x.2+2x.3x-2x.1-3.3x+3.1\\ =10x^2+4x+6x^2-2x-9x+3\\ =16x^2-7x+3\)

1: \(=6x^2+2x-15x-5-x^2+6x-9+4x^2+20x+25-27x^3-27x^2-9x-1\)

=-27x^3-18x^2+4x+10

2: =4x^2-1-6x^2-9x+4x+6-x^3+3x^2-3x+1+8x^3+36x^2+54x+27

=7x^3+37x^2+46x+33

5:

\(=25x^2-1-x^3-27-4x^2-16x-16-9x^2+24x-16+\left(2x-5\right)^3\)

\(=8x^3-60x^2+150-125+12x^2-x^3+8x-60\)

=7x^3-48x^2+8x-35

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

`=6x^2-2x-2x^2+6x-x+3`

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

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

`=3x^2-9x-4x^2+4x-2x+2`

`=-x^2-7x+2`

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

`=3x^2-15x-(x^2-4x+4)-(4x^2-9)`

`=3x^2-15x-x^2+4x-4-4x^2+9`

`=-2x^2-11x+5`

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

`=4x^2-12x+9+2x^2+8x-x-4`

`=6x^2-5x+5`

1) \(\left(x+1\right)^2=x^2+2x+1\)

2) \(\left(2x+1\right)^2=4x^2+4x+1\)

3) \(\left(2x+y\right)^2=4x^2+4xy+y^2\)

4) \(\left(2x+3\right)^2=4x^2+12x+9\)

5) \(\left(3x+2y\right)^2=9x^2+12xy+4y^2\)

6) \(\left(2x^2+1\right)^2=4x^4+4x^2+1\)

7) \(\left(x^3+1\right)^2=x^6+2x^3+1\)

8) \(\left(x^2+y^3\right)^2=x^4+2x^2y^3+y^6\)

9) \(\left(x^2+2y^2\right)^2=x^4+4x^2y^2+4y^4\)

10) \(\left(\dfrac{1}{2}x+\dfrac{1}{3}y\right)^2=\dfrac{1}{4}x^2+\dfrac{1}{3}xy+\dfrac{1}{9}y^2\)

Phần b) = 3

sao bạn ko làm hẳn ra cho bạn ý

1. Thu gọn:

a) 5x. (x-3) - x. (5x+1)

= 5x² - 15x - 5x² - x = -16x

b) -3x. (x-1) - x. (x+1) + 4x. (x-2)

= -3x² + 3x - x² - x + 4x² - 8x

= -6x