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25 tháng 10 2016

Đặt \(\frac{x}{3}=\frac{y}{4}=k\)\(\Rightarrow x=3k;y=4k\)

\(\Rightarrow xy=300\Leftrightarrow3k\cdot4k=300\)

\(\Leftrightarrow12k^2=300\)

\(\Leftrightarrow k^2=25\Leftrightarrow k=\pm5\)

  • Nếu \(k=5\Rightarrow\)\(\begin{cases}x=3k=3\cdot5=15\\y=4k=4\cdot5=20\end{cases}\)
  • Nếu \(k=-5\Rightarrow\)\(\begin{cases}x=3k=3\cdot\left(-5\right)=-15\\y=4k=4\cdot\left(-5\right)=-20\end{cases}\)
25 tháng 10 2016

Từ \(\frac{x}{3}=\frac{y}{4}=k\Rightarrow\begin{cases}x=3k\\y=4k\end{cases}\)

Vì xy = 300 => 3k.4k = 300 => 122 = 300 => k2 = 25 => k = \(\pm\) 5

Với k = 5 => \(\begin{cases}x=15\\y=20\end{cases}\)

Với k = -5 => \(\begin{cases}x=-15\\y=-20\end{cases}\)

21 tháng 12 2022

ta có : `x/2 = y/3 = z/4=> (2x)/4 =(3y)/9 = z/4`

`=> (2x)/4 =(3y)/9 = z/4` và `2x + 3y - z = 27`

Áp dụng t/c dãy tỉ số bằng nhau ta có:

`(2x)/4 =(3y)/9 = z/4 =(2x + 3y - z)/(4+9-4)=27/9=3`

`=>x/2=3=>x=3.2=6`

`=>y/3=3=>x=3.3=9`

`=>z/4=3=>z=3.4=12`

28 tháng 7 2023

Ta có: 

\(x^4=y^4\)

\(\Rightarrow x^4-y^4=0\)

\(\Rightarrow\left(x^2\right)^2-\left(y^2\right)^2=0\)

\(\Rightarrow\left(x^2-y^2\right)\left(x^2+y^2\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x^2-y^2=0\\x^2+y^2=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x-y=0\\x+y=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=y\\x=-y\end{matrix}\right.\)

_______________

Ta có: 

\(x^5=y^5\)

\(\Rightarrow x^5-y^5=0\)

\(\Rightarrow x-y=0\)

\(\Rightarrow x=y\)

20 tháng 5 2021

ko giới hạn giá trị hả bạn?

20 tháng 5 2021

Nếu thế thì y có thể là ifinity mà?

8 tháng 9 2021

\(\dfrac{x}{3}=x+y=20\Rightarrow x=60\Rightarrow60+y=20\Rightarrow y=-40\)

8 tháng 9 2021

Ta có:

\(\dfrac{x}{3}=20\)

\(\Rightarrow\)\(x=60\)

Lại có:

\(x+y=20\)

\(\Rightarrow\)\(y=20-60\)

\(\Rightarrow\)\(y=-40\)

Vây x = 60 và y = - 40

15 tháng 8 2021

áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{2x}{4}=\dfrac{3y}{9}=\dfrac{2x-3y}{4-9}=-\dfrac{54}{5}\)

\(\dfrac{x}{2}=-\dfrac{54}{5}\Rightarrow x=-\dfrac{54}{5}.2=-\dfrac{108}{5}\)

\(\dfrac{y}{3}=-\dfrac{54}{5}\Rightarrow y=-\dfrac{54}{5}.3=-\dfrac{162}{5}\)

Vậy \(x=-\dfrac{108}{5};y=-\dfrac{162}{5}\)

 

Ta có: \(\dfrac{x}{2}=\dfrac{y}{3}\)

nên \(\dfrac{2x}{4}=\dfrac{3y}{9}\)

mà 2x-3y=54

nên Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

\(\dfrac{2x}{4}=\dfrac{3y}{9}=\dfrac{2x-3y}{4-9}=\dfrac{-54}{5}\)

Do đó: \(x=-\dfrac{108}{5};y=-\dfrac{162}{5}\)

18 tháng 12 2021

help me , giúp mình với 

khocroi

5 tháng 2 2022

7 nha  

HT

\(\Leftrightarrow xy=63\)

\(\Leftrightarrow\left(x,y\right)\in\left\{\left(1;63\right);\left(3;21\right);\left(7;9\right);\left(-63;-1\right);\left(-21;-3\right);\left(-9;-7\right)\right\}\)

\(\dfrac{x}{3}-\dfrac{1}{y+1}=\dfrac{1}{6}\)

=>\(\dfrac{xy+x-3}{3\left(y+1\right)}=\dfrac{1}{6}\)

=>\(2\left(xy+x-3\right)=1\)

=>2xy+2x-6=1

=>2xy+2x=7

=>2x(y+1)=7

=>x(y+1)=7/2

mà x,y nguyên

nên \(\left(x,y\right)\in\varnothing\)

1 tháng 2

1/y+1=x/3-1/6

1/y+1=2x/6-1/6

1/y+1= 2x-1/6

=> 1.6=(y+1).(2x-1)

ta có bảng

y+1     6      1       

Past lives couldn't ever hold me down
Lost love is sweeter when it's finally found
I've got the strangest feeling
This isn't our first time around Past lives couldn't ever come between us
Sometimes the dreamers finally wake up
Don't wake me I'm not dreaming
Don't wake me I'm not dreaming All my past lives they got nothing on me
Golden eagle you're the one and only flying high
Through the cities in the sky I'll take you way back, countless centuries
Don't you remember that you were meant to be
My Queen of Hearts, meant to be my love Through all of my lives
I'd never thought I'd wait so long for you
The timing is right
The stars are aligned So save that heart for me
'Cause girl you know that you're my destiny (d-destiny)
Swear to the moon, the stars, the sons and the daughters
Our love is deeper than the oceans of water I need you now, I've waited oh so long
(Gimme love)
I need you now, I've waited oh so long Passing seasons, empty bottles of wine
My ancient kingdom came crashing down without you
Baby child, I'm lost without your love Diamond sparrow, my moonlit majesty
You know I need you, come flying back to me Through all of my lives
I'd never thought I'd wait so long for you
The timing is right
The stars are aligned So save that heart for me
'Cause girl you know that you're my destiny (d-destiny)
Respect to the moon, the stars, their sons and their daughters
Our love is deeper than the oceans of water Save that heart for me
And girl I'll give you everything you need (everything you need)
Here's to our past lives, our mothers and fathers
Our love is deeper than the oceans of water I need you now, I've waited oh so long, yeah
(Gimme love)
I need you now, I've waited oh so long I need you now, I've waited oh so long, yeah
(Gimme love)
I need you now, I've waited oh so long So save that heart for me
'Cause girl you know that you're my destiny (d-destiny)
Respect to the moon, the stars, their sons and their daughters
Our love is deeper than the oceans of water Save that heart for me
And girl I'll give you everything you need (everything you need)
Here's to our past lives, our mothers and fathers
Our love is deeper than the oceans of wat

2x-1    1      6         ...

y         5      0

x        1       7/2

                   loại