Question

1.Tìm x: a, 3(2x-1)(3x-1)-(2x-3)(9x-1)=0

b, 4(x+1)²+(2x-1)²-8(x-1)(x+1)=11

c, (x-3)(x²+3x+9)+x(x+2)(2-x)=1

2. Rút gọn biểu thức

a, (2x-3y)(2x+3y)-4(x-y)²-8xy

b, (x-2)³-x(x+1)(x-1)+6x(x-3)

c, (x-2)(x²-2x+4)(x+2)(x²+2x+4)

Answer 1

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

Answer 2

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

Answer 3

câu 1 a. sai .kết quả =0