bài 1 

a, \(\left(3x-2\right)^2=9x^2-12x+4\)

b,\(\left(5-3t\right)^2=25-30t+9t^2\)

c, \(\left(y-5\right)\left(y+5\right)=y^2-25\)

d, \(\left(3-x^2\right)^2=9-6x^2+x^4\)

e, \(\left(a^2+\frac{3}{5}b\right)\left(a^2-\frac{3}{5}b\right)=a^4-\frac{9}{25}b^2\)

q,\(15\left(-\frac{1}{4}x+\frac{4}{5}v\right)^2=15\left(\frac{1}{16}x^2-\frac{1}{5}xv+\frac{16}{25}v^2\right)\)

\(=\frac{15}{16}x^2-3xv+\frac{15.16}{25}v^2\)

bài 2 : câu a sửa đề thành +1 thôi

a, \(16u^2v^4-8uv^2+1=\left(4uv^2\right)^2-2.\left(4uv^2\right)+1^2=\left(4uv^2-1\right)^2\)

b,\(4x^2-4x+1=\left(2x\right)^2-2.2x+1=\left(2x-1\right)^2\)

c, \(\frac{x^2}{4}-3x+4=\left(\frac{x}{2}\right)^2-2.\frac{x}{2}.3+3^2-5\)

\(=\left(\frac{x}{2}-3\right)^2-\sqrt{5}^2=\left(\frac{x}{2}-3-\sqrt{5}\right)\left(x^2-3+\sqrt{5}\right)\)

d, \(\left(2n-m\right)^2+2\left(2n-m\right)+1=\left(2n-m+1\right)^2\)

e, \(23v^2-10v+1=\left(5v\right)^2-2.5v+1-2v^2\)

\(=\left(5v-1\right)^2-\left(\sqrt{2}v\right)^2=\left(5v-1-\sqrt{2}v\right)\left(5v-1+\sqrt{2}v\right)\)

g, \(x^2+10x+25=\left(x+5\right)^2\)

35 + 15x = 65

        15x = 65 - 35

        15x = 30

           x = 30 : 15

           x = 2.

nếu sai mong mn sửa giúp!

 35 + 15x = 65

<=> 15X = 65 - 35

<=> 15x = 30

<=> x = 30 : 15

<=> x = 2

Vậy x = 2

x( x + 2 )² - ( x - 1 )³

= x( x² + 4x + 4 ) - ( x³ - 3x² + 3x - 1 )

= x³ + 4x² + 4x - x³ + 3x² - 3x + 1

= 7x² + x + 1 

4x( x + 5 ) + ( 3 - 2x )( 2x + 3 )

= 4x² + 20x + 9 - 4x²

= 20x + 9

( x - 3 )³ - ( x + 3 )³ 

= x³ - 9x² + 27x - 27 - ( x³ + 9x² + 27x + 27 )

= x³ - 9x² + 27x - 27 - x³ - 9x² - 27x - 27

= -18x² - 54

x( 2x - 7 ) - 2( x + 3 )²

= 2x² - 7x - 2( x² + 6x + 9 )

= 2x² - 7x - 2x² - 12x - 18

= -19x - 18

\(x\left(x+2\right)^2-\left(x-1\right)^3\)

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

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

\(=7x^2+x+1\)

Ta có:35+15x=65

15x=65-35

15x=30

x=30÷15

x=2

Vậy :x=2

:))k nhé!Học tốt!

35+15x=65

15x=65-35

15x=30

x=30:15

x=2

vậy x=2

( 2 + x ) + ( 4 + x ) + ( 6 + x ) + ... + ( 52 + x ) = 780

2 + x + 4 + x + 6 + x + ... + 52 + x =780 ( đây là bước phá ngoặc )

( 2 + 4 + 6 + ... + 52 ) + ( x + x + x + ... + x ) ( có 26 số x) = 780

702 + 26.x   = 780 

26.x             = 780 - 702 ( dấu chấm là dấu nhân nhé

26.x             = 78

x                  = 78 : 26

x                  = 3

       Vậy x = 3

( cho mình 1 t i c k nhé :))

1. dữ dằn

2.nhô

3.sáng trưng

4.gầm gào

5.hối hả

( ý kiến riêng của mình . Nếu đúng cho mình 1 t i c k nhé :)))

\(x\cdot12,25-x+x\cdot2,75=1050\)

\(\Rightarrow x\cdot12,25-x\cdot1+x\cdot2,75=1050\)

\(\Rightarrow x\left(12,25-1+2,75\right)=1050\)

\(\Rightarrow x\cdot14=1050\)

\(\Rightarrow x=\frac{1050}{14}=75\)

dau . la dau j vay ban