Cho biết x ∈ N và (327.x + 2 4).7 3 = 7.7 5
Ta có x = ?
1. tìm x biết x+2/327 + x+3/326 + x+4/325 + x+5/324 + x+349/5 = 0
2.CMR:n thuộc N* thì 3^n+2 - 2^n+2 + 3^n - 2^n chia hết cho 10
Tìm x biết
a,x+2/327+x+3/326+x+4/325+x+5/324+x+349/5=0
b,|5x-3|>=7
Tìm x biết
a,x+2/327+x+3/326+x+4/325+x+5/324+x+349/5=0
b,|5x-3|>=7
2. Tìm x thuộc N biết :
a) 3^x = 87
b) 2^3 . 2^x = 64
c) 7.7^x + 1 = 343
d) (2x-2)^3 + 75 = 139
tìm x biết x+2/327+x+3/326+x+4/325+x+5/324=-4
tc tỉ lệ thức,ta có (ra số hơi to thông cảm )
\(\Leftrightarrow\frac{22990993x+80556557}{1870865100}=-\frac{4}{1}\Rightarrow\left(22990993x+80556557\right)1=-1870865100.4\)
\(\frac{\left(22990993x+80556557\right)1}{22990933x}=-\frac{1870865100.4}{22990993x}\)( chia 2 vế cho 2290933x)
\(\Rightarrow\frac{22990933x+80556557}{22990933x}=-\frac{1870865100.4}{22990933x}\)
=>x=-329
tìm x biết x+2/327+x+3/326+x+4/325+x+5/324=-4 vậy x=
tìm x, biết :
(x+2)/327 + (x+3)/326 + (x+4)/325 + (x+5)/324 = -4
\(\frac{x+2}{327}+\frac{x+3}{326}+\frac{x+4}{325}+\frac{x+5}{324}=-4\)
<=>\(\left(\frac{x+2}{327}+1\right)+\left(\frac{x+3}{326}+1\right)+\left(\frac{x+4}{325}+1\right)+\left(\frac{x+5}{324}+1\right)=0\)
<=>\(\frac{x+329}{327}+\frac{x+329}{326}+\frac{x+329}{325}+\frac{x+329}{324}=0\)
<=>\(\left(x+329\right)\left(\frac{1}{327}+\frac{1}{326}+\frac{1}{325}+\frac{1}{324}\right)=0\)
Vì \(\frac{1}{327}+\frac{1}{326}+\frac{1}{325}+\frac{1}{324}\ne0\Rightarrow x+329=0\Leftrightarrow x=-329\)
Tìm x,y,z biết:
\(\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{327}+\dfrac{x+5}{325}+\dfrac{x+349}{5}=0\)
Sửa đề: Tìm x \(\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{325}+\dfrac{x+5}{324}+\dfrac{x+349}{5}=0\)
Bài giải
\(\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{325}+\dfrac{x+5}{324}+\dfrac{x+349}{5}=0\)
\(\Leftrightarrow\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{325}+\dfrac{x+5}{324}+\dfrac{x+329+20}{5}=0\)
\(\Leftrightarrow\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{325}+\dfrac{x+5}{324}+\dfrac{x+329}{5}+\dfrac{20}{5}=0\)
\(\Leftrightarrow\dfrac{x+2}{327}+\dfrac{x+3}{326}+\dfrac{x+4}{325}+\dfrac{x+5}{324}+\dfrac{x+329}{5}+4=0\)
\(\Leftrightarrow\dfrac{x+2}{327}+1+\dfrac{x+3}{326}+1+\dfrac{x+4}{325}+1+\dfrac{x+5}{324}+1+\dfrac{x+329}{5}=0\)
\(\Leftrightarrow\dfrac{x+329}{327}+\dfrac{x+329}{326}+\dfrac{x+329}{325}+\dfrac{x+329}{324}+\dfrac{x+329}{5}=0\)
\(\Leftrightarrow\left(x+329\right)\left(\dfrac{1}{327}+\dfrac{1}{326}+\dfrac{1}{325}+\dfrac{1}{324}+\dfrac{1}{5}\right)=0\)
\(\Rightarrow x+329=0\). Do \(\dfrac{1}{327}+\dfrac{1}{326}+\dfrac{1}{325}+\dfrac{1}{324}+\dfrac{1}{5}\ne0\)
\(\Rightarrow x=-329\)
tìm x biết: (x+2)/327+(x+3)/326+(x+4)/325+(x+5)/324+(x+329)/5 = -4