a: \(\dfrac{5}{6xy^2}=\dfrac{5\cdot3\cdot x}{18x^2y^2}=\dfrac{15x}{18x^2y^2}=\dfrac{15x^2}{18x^3y^2}\)

\(\dfrac{2}{9x^3y}=\dfrac{2\cdot2y}{18x^3y^2}=\dfrac{4y}{18x^3y^2}\)

b: \(\dfrac{5}{14x^2y}=\dfrac{5\cdot y^4\cdot3}{42x^2y^5}=\dfrac{15y^4}{42x^2y^5}\)

\(\dfrac{4}{21xy^5}=\dfrac{4\cdot2\cdot x}{42x^2y^5}=\dfrac{8x}{42x^2y^5}\)

c: \(\dfrac{2x}{\left(x+2\right)^3}=\dfrac{4x^2}{2x\left(x+2\right)^3}\)

\(\dfrac{x-2}{2x\left(x+2\right)^2}=\dfrac{\left(x-2\right)\left(x+2\right)}{2x\left(x+2\right)^3}=\dfrac{x^2-4}{2x\left(x+2\right)^3}\)

d: \(\dfrac{7x-1}{2x^2+6x}=\dfrac{7x-1}{2x\left(x+3\right)}=\dfrac{\left(7x-1\right)\left(x-3\right)}{2x\left(x+3\right)\left(x-3\right)}\)

\(\dfrac{5-3x}{x^2-9}=\dfrac{2x\left(5-3x\right)}{2x\left(x-3\right)\left(x+3\right)}\)

f: \(\dfrac{x-1}{2x+2}=\dfrac{\left(x-1\right)^2}{2\left(x+1\right)\left(x-1\right)}\)

\(\dfrac{x+1}{2x-2}=\dfrac{\left(x+1\right)^2}{2\left(x-1\right)\left(x+1\right)}\)

\(\dfrac{1}{x^2-1}=\dfrac{2}{2\left(x-1\right)\left(x+1\right)}\)

2:

a: Khi x=36 thì \(A=\dfrac{6+5}{6-3}=\dfrac{11}{3}\)

b: \(B=\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)+\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)-x+4\sqrt{x}+9}{x-9}\)

\(=\dfrac{x+\sqrt{x}-6+x-2\sqrt{x}-3-x+4\sqrt{x}+9}{x-9}\)

\(=\dfrac{x+3\sqrt{x}}{x-9}=\dfrac{\sqrt{x}}{\sqrt{x}-3}\)

c: B/A=2

=>\(\dfrac{\sqrt{x}}{\sqrt{x}-3}:\dfrac{\sqrt{x}+5}{\sqrt{x}-3}=2\)

=>\(\dfrac{\sqrt{x}}{\sqrt{x}+5}=2\)

=>2*căn x+10=căn x

=>căn x=-10(loại)

A=   (\(x-y\))² - (y-z)²

A = (\(x-y\) - y + z)(\(x-y\) + y -  z)

A = ( \(x\) - 2y + z)(\(x-z\))

Trả lời nhanh giúp mình

oki bạn

x^2+y^2-2x-4y+6=1-(x-y+1)^2

=>x^2-2x+1+y^2-4y+4=-(x-y+1)^2

=>(x-1)^2+(y-2)^2=-(x-y+1)^2

=>(x-1)^2+(y-2)^2+(x-y+1)^2=0

=>x=1;y=2

A=2022+2023*2

=2022+4046

=6068

`@` `\text {Ans}`

`\downarrow`

`18,`

`2^(3x+1) = 16`

`=> 2^(3x + 1) = 2^4`

`=> 3x+1 = 4`

`=> 3x = 4 - 1`

`=> 3x = 3`

`=> x = 1`

Vậy, `x = 1`

`=> A`

`19,`

`9^12 * 27^5`

`= (3^2)^12 * (3^3)^5`

`= 3^24 * 3^15`

`=3^39`

`=> D`

`20,`

`100 < 5^(2x - 1) < 5^5`

`=> 2x - 1 < 5`

`=> x < 3 => x \in {0; 1; 2}`

`=> D`

`21,`

`5^x < 90`

`=> x < 3`

`=> x \in {0; 1; 2}`

`=> B`

`22,`

`(7x - 11)^3 = 5^2 * 2^5 + 200`

`=> (7x - 11)^3 = 25 * 32 + 200`

`=> (7x - 11)^3 = 800 + 200`

`=> (7x - 11)^3 = 1000`

`=> (7x - 11)^3 = 10^3`

`=> 7x - 11 = 10`

`=> 7x = 21`

`=> x = 3`

`=> C`

`23,`

`(x - 4)^5 = (x - 4)^4`

`=> (x - 4)^5 - (x - 4)^4 = 0`

`=> (x - 4)^4 * (x - 4 - 1) = 0`

`=> \text {TH1:} (x - 4)^4 = 0`

`=> x - 4 = 0`

`=> x = 4`

`\text {TH2:} x - 4 - 1 = 0`

`=> x - 5 = 0`

`=> x = 5`

Tổng của `2` stn x thỏa mãn dk là: `4 + 5 = 9`

`=> A.`

mình cảm ơn

72^3*54^2=1088391168

108^4=136048896

bạn chấm điểm cho mik với nhé ;)))

câu b 

3^10.11+3^10x5  = 3^10.16  = 3.3.3^8.2.8   =3^8.2

   39.24                      39.24       3.13.3.8         13

mik ghi xuống dòng như vậy là giống phân số á bn, lm đúng ko thì ko chắc :)))

(x+y)³-x(x+y)²=(x+y)²(x+y-x)=(x+y)²y

cám ơn bạn nha!!!

Tham khảo:

1) Ta có:888+88+8+8+8=1000 ⇒ 8 chữ số 8 cộng lại có thể bằng 1000

2) Minh phá vỡ kỉ lục thế giới

1) 888+88+8+8+8=1000

2) phá vỡ kỉ lục