a: \(\left(x+8\right)^2-2\left(x+8\right)\left(x-2\right)+\left(x-2\right)^2\)

\(=\left(x+8-x+2\right)^2=10^2=100\)

b: \(=x\left(x^2-16\right)-\left(x^4-1\right)\)

\(=x^3-16x-x^4+1\)

c: \(=2\left(2x^2-3xy+6xy-9y^2\right)-\left(4x^2-4x+1\right)+9y^2-6y+1\)

\(=4x^2+6xy-18y^2-4x^2+4x-1+9y^2-6y+1\)

\(=6xy-9y^2+4x-6y\)

1)a)3(2x-1)(3x-1)-(2x-3)(9x-1)=0

<=>18x²-15x+1-18x²+29x-3=0

<=>14x-2=0

<=>14x=2

<=>x=1/7

b)4(x+1)²+(2x-1)²-8(x-1)(x+1)=11

<=>4x²+8x+4+4x²-4x+1-8x²+8=11

<=>4x+13=11

<=>4x=11-13

<=>4x=-2

<=>x=-1/2

c)Sai đề phải là dấu - chứ không phải +

(x-3)(x²+3x+9)-x(x-2)(x+2)=1

<=>x³-27-x³+4x=1

<=>4x=1+27

<=>4x=28

<=>x=7

2)a)(2x-3y)(2x+3y)-4(x-y)²-8xy

=4x²-9y²-4x²+8xy-4y²-8xy

=-13y²

b)(x-2)³-x(x+1)(x-1)+6x(x-3)

=x³-6x²+12x+8-x³+x+6x²-18x

=8-5x

c)(x-2)(x²-2x+4)(x+2)(x²+2x+4)

=(x-2)(x²+2x+4)(x+2)(x²-2x+4)

=(x³-8)(x³+8)

=x⁶-64

Nguyễn Diệu Thảo sap c hk **** cho  Moon Light

câu 1 a. sai .kết quả =0

A = (3x + y)^2 - 3y . ( 2x - 1/3y )

=2y²+9x²

B = ( x - 2 )^2 + ( x + 2 )^2 - 2. ( x - 2 ) ( x + 2)

=2⁴

C = ( x - y ) ( x^2 + xy + y^2 ) + 2y^3

=y³+x³

D = ( x -5 ) ( x+ 5 ) -(x - 8 ) (x + 4)

=4x+7

E = (3x + 1 )^2 - 2 . ( 9x^2 - 1 ) + ( 3x - 1 ) ^2

=4

F = ( x - 3 ) ( x + 3 ) - ( x - 3 )^2

=6x-18

\(a,\left(2x-1\right)^2-\left(x-3\right)\left(x+3\right)-1969\\ =4x^2-4x+1-x^2+9-1969\\ =3x^2-4x-1959\)

\(b,\left(2x-3y\right)\left(2x+3y\right)-\left(2x-y\right)^2\\ =4x^2-9y^2-4x^2+4xy-y^2\\ =8y^2+4xy=4y\left(2y+x\right)\)

\(c,\left(x+3y\right)^2+\left(x+y\right)\left(x-y\right)+280\\ =x^2+6xy+9y^2+x^2-y^2+280\\ =2x^2+8y^2+6xy+280\)

a: \(\left(2x-1\right)^2-\left(x-3\right)\cdot\left(x+3\right)-1969\)

\(=4x^2-4x+1-x^2+9-1969\)

\(=3x^2-4x-1959\)

b: \(\left(2x-3y\right)\left(2x+3y\right)-\left(2x-y\right)^2\)

\(=4x^2-9y^2-4x^2+4xy-y^2\)

\(=-10y^2+4xy\)

a)\(\text{( 2 x − 1 )^2− ( x − 3 ) ( x + 3 ) − 1969}\)

\(\text{= 4x^2 − 4x + 1 − x^2 + 9 − 1969}\)

\(\text{=3x^2− 4 x − 1959}\)

b) \(\text{( 2 x − 3 y ) ( 2 x + 3 y ) − ( 2 x − y )^2}\)

=\(\text{= 4 x^2− 9 y^2− 4 x^2 + 4 x y − y^2}\)

\(\text{= -10 y^2+ 4 x y = -2 y ( 5 y -2 x )}\)

c)\(\text{( x + 3 y )^2 + ( x + y ) ( x − y ) + 280}\)

\(\text{= x^2 + 6 x y + 9 y^2 + x^2 − y^2 + 280}\)

\(\text{= 2 x^2 + 8 y^2 + 6 x y + 280}\)

Bài 1.

a)

\((x-2)(2x-1)-(2x-3)(x-1)-2\\=2x^2-x-4x+2-(2x^2-2x-3x+3)-2\\=2x^2-5x+2-(2x^2-5x+3)-2\\=2x^2-5x+2-2x^2+5x-3-2\\=(2x^2-2x^2)+(-5x+5x)+(2-3-2)\\=-3\)

b)

\(x(x+3y+1)-2y(x-1)-(y+x+1)x\\=x^2+3xy+x-2xy+2y-xy-x^2-x\\=(x^2-x^2)+(3xy-2xy-xy)+(x-x)+2y\\=2y\)

Bài 2.

a)

\((14x^3+12x^2-14x):2x=(x+2)(3x-4)\\\Leftrightarrow 14x^3:2x+12x^2:2x-14x:2x=3x^2-4x+6x-8\\ \Leftrightarrow 7x^2+6x-7=3x^2+2x-8\\\Leftrightarrow (7x^2-3x^2)+(6x-2x)+(-7+8)=0\\\Leftrightarrow 4x^2+4x+1=0\\\Leftrightarrow (2x)^2+2\cdot 2x\cdot 1+1^2=0\\\Leftrightarrow (2x+1)^2=0\\\Leftrightarrow 2x+1=0\\\Leftrightarrow 2x=-1\\\Leftrightarrow x=\frac{-1}2\)

b)

\((4x-5)(6x+1)-(8x+3)(3x-4)=15\\\Leftrightarrow 24x^2+4x-30x-5-(24x^2-32x+9x-12)=15\\\Leftrightarrow 24x^2-26x-5-(24x^2-23x-12)=15\\\Leftrightarrow 24x^2-26x-5-24x^2+23x+12=15\\\Leftrightarrow -3x+7=15\\\Leftrightarrow -3x=8\\\Leftrightarrow x=\frac{-8}3\\Toru\)