2×(1/3):y = 3×(1/2) Tìm y
Tìm y
a) 3 \(\dfrac{1}{5}\) : 2\(\dfrac{1}{3}\): y = \(\dfrac{12}{7}\)
b) 3 : y x 3 \(\dfrac{1}{2}\)= \(\dfrac{2}{3}x\dfrac{3}{4}\)
c) \(3\dfrac{2}{3}-y+1\dfrac{3}{4}=2\)
mình ko chép đề bài nha
a) \(\dfrac{16}{5}\): \(\dfrac{7}{3}\) : y =\(\dfrac{12}{7}\)
\(\dfrac{48}{35}\): y = \(\dfrac{12}{7}\)
y = \(\dfrac{48}{35}\): \(\dfrac{12}{7}\)
y = \(\dfrac{4}{5}\)
b) 3 : y x \(\dfrac{7}{2}\)= \(\dfrac{1}{2}\)
3 : y = \(\dfrac{1}{2}:\dfrac{7}{2}\)
3 : y = \(\dfrac{1}{7}\)
y = 3 : \(\dfrac{1}{7}\)
y = 21
Bài 1 : Tìm x ,y,z biết:
a, 3/x-1 = 4/y-2 = 5/z-3 và x+y+z = 18
b, 3/x-1 = 4/y-2 = 5/z-3 và x.y.z = 192
Bài 2 : Tìm x,y,z biết : x^3+y^3/6 = x^3-2y^3/4 và x^6.y^6 = 64
Bài 3 : Tìm x,y,z biết :x+4/6 = 3y-1/8 = 3y-x-5/x
Bài 4 :Tìm x,y,z biết : x+y+2005/z = y+z-2006 = z+x+1/y = 2/x+y+z
bài 1 : a,ta có 3/x-1 =4/y-2=5/z-3 => x-1/3=y-2/4=z-3/5
áp dụng .... => x-1+y-2+z-3 / 3+4+5 = x+y+z-1-2-3/3+4+5 = 12/12=1
do x-1/3 = 1 => x-1 = 3 => x= 4 ( tìm y,z tương tự
Bài 1:
a) Ta có: 3/x - 1 = 4/y - 2 = 5/z - 3 => x - 1/3 = y - 2/4 = z - 3/5 áp dụng ... =>x - 1 + y - 2 + z - 3/3 + 4 + 5 = x + y + z - 1 - 2 - 3/3 + 4 + 5 = 12/12 = 1 do x - 1/3 = 1 => x - 1 = 3 => x = 4 ( tìm y, z tương tự )
Tìm y để
1/y(y+1) + 1/(y+1)(y+2) + 1/(y+2)(y+3) + 1/(y+3)(y+4)= 1/15
\(\frac{1}{y\left(y+1\right)}\) + \(\frac{1}{\left(y+1\right)\left(y+2\right)}\) + \(\frac{1}{\left(y+2\right)\left(y+3\right)}\) + \(\frac{1}{\left(y+3\right)\left(y+4\right)}\)= \(\frac{1}{15}\)
\(\frac{1}{y}\) - \(\frac{1}{y+1}\) + \(\frac{1}{y+1}\) - \(\frac{1}{y+2}\) + \(\frac{1}{y+2}\) - \(\frac{1}{y+3}\) + \(\frac{1}{y+3}\) - \(\frac{1}{y+4}\) = \(\frac{1}{15}\)
\(\frac{1}{y}\) + \(\frac{1}{y+1}\) - \(\frac{1}{y+1}\) + \(\frac{1}{y+2}\) - \(\frac{1}{y+2}\) + \(\frac{1}{y+3}\) - \(\frac{1}{y+3}\) - \(\frac{1}{y+4}\) = \(\frac{1}{15}\)
\(\frac{1}{y}\) - \(\frac{1}{y+4}\) = \(\frac{1}{15}\)
\(\frac{4}{y\left(y+4\right)}\) = \(\frac{1}{15}\) => \(\frac{4}{y\left(y+4\right)}\)= \(\frac{4}{60}\)
=> y(y+4)=60 Mà 60 = 1.60=2.30=3.20=4.15=5.12=6.10
Vậy y(y+4)=6.10 => y=6. Vậy y=6
Tìm y để
1/y(y+1) + 1/(y+1)(y+2) + 1/(y+2)(y+3) + 1/(y+3)(y+4) = 1/15
1.tìm x,y biết
a, x.(y-3)≥0
b, (2.x-1).(y-1)≤0
c,(x-1).(2.k+1)≥0
2. tìm x,y ϵ Z biết
a, x(x+3)=0
b,(x-2).(5-x)=0
c,(x-1).(x^2+1)=0
d, x.y+3.x-7.y=21
e,x.y+3.x-2y=11
Bài 2:
a: =>x=0 hoặc x+3=0
=>x=0 hoặc x=-3
b: =>x-2=0 hoặc 5-x=0
=>x=2 hoặc x=5
c: =>x-1=0
hay x=1
3. Tìm tập xác định của các hàm số sau:
a) \(y = 2^{x^2-1}\)
b) \(y = x^{-4}\)
c) \(y = (x-1)^{-3}\)
d) \(y = (x^2-1)^{4\pi}\)
e) \(y = \ln (4x^2-1)\)
f) \(y = \log_{3} (x^2-2)\)
h) \(y = (2x^2-4x)^{\frac{-1}{3}}\)
k) \(y = (2x-1)^{-4}\)
l) \(y = \log_{3} (x^2-1) + \ln (x-2) + e^{\frac{x}{x-1}}\)
`a)TXĐ: R`
`b)TXĐ: R\\{0}`
`c)TXĐ: R\\{1}`
`d)TXĐ: (-oo;-1)uu(1;+oo)`
`e)TXĐ: (-oo;-1/2)uu(1/2;+oo)`
`f)TXĐ: (-oo;-\sqrt{2})uu(\sqrt{2};+oo)`
`h)TXĐ: (-oo;0) uu(2;+oo)`
`k)TXĐ: R\\{1/2}`
`l)ĐK: {(x^2-1 > 0),(x-2 > 0),(x-1 ne 0):}`
`<=>{([(x > 1),(x < -1):}),(x > 2),(x ne 1):}`
`<=>x > 2`
`=>TXĐ: (2;+oo)`
1. Tìm tập xác định của các hàm số sau:
a) \(y = 3(x-1)^{-3}\)
b) \(y = (2 - x^2)^{\frac{2}{5}}\)
c) \(y = (x^2 + x - 6)^{\frac{-1}{3}}\)
d) \(y = \left(\dfrac{1}{x^2-1}\right)^3\)
e) \(y = \log_{3} (x^2-2)\)
f) \(y = \log_{\frac{1}{2}}\sqrt{x-1}\)
g) \(y = \log_{\pi} (x^2+x-6)\)
d: ĐKXĐ: \(x^2-1< >0\)
=>\(x^2\ne1\)
=>\(x\notin\left\{1;-1\right\}\)
Vậy: TXĐ là D=R\{1;-1}
b: ĐKXĐ: \(2-x^2>0\)
=>\(x^2< 2\)
=>\(-\sqrt{2}< x< \sqrt{2}\)
Vậy: TXĐ là \(D=\left(-\sqrt{2};\sqrt{2}\right)\)
a: ĐKXĐ: \(x-1>0\)
=>x>1
Vậy: TXĐ là \(D=\left(1;+\infty\right)\)
c: ĐKXĐ: \(x^2+x-6>0\)
=>\(x^2+3x-2x-6>0\)
=>\(\left(x+3\right)\left(x-2\right)>0\)
TH1: \(\left\{{}\begin{matrix}x+3>0\\x-2>0\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x>2\\x>-3\end{matrix}\right.\)
=>x>2
TH2: \(\left\{{}\begin{matrix}x+3< 0\\x-2< 0\end{matrix}\right.\)
=>\(\left\{{}\begin{matrix}x< -3\\x< 2\end{matrix}\right.\)
=>x<-3
Vậy: TXĐ là \(D=\left(2;+\infty\right)\cup\left(-\infty;-3\right)\)
e: ĐKXĐ: \(x^2-2>0\)
=>\(x^2>2\)
=>\(\left[{}\begin{matrix}x>\sqrt{2}\\x< -\sqrt{2}\end{matrix}\right.\)
Vậy: TXĐ là \(D=\left(-\infty;-\sqrt{2}\right)\cup\left(\sqrt{2};+\infty\right)\)
f: ĐKXĐ: \(\sqrt{x-1}>0\)
=>x-1>0
=>x>1
Vậy: TXĐ là \(D=\left(1;+\infty\right)\)
g: ĐKXĐ: \(x^2+x-6>0\)
=>\(\left(x+3\right)\left(x-2\right)>0\)
=>\(\left[{}\begin{matrix}x>2\\x< -3\end{matrix}\right.\)
Vậy: TXĐ là \(D=\left(2;+\infty\right)\cup\left(-\infty;-3\right)\)
tìm y;
Y x 3/1/3=3/1/3 : 4/1/4
hỗn số đó
5/2/3: Y =3/2/3-2/1/2