Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a)\(x-15\%x=\frac{1}{3}\)
\(x.\left(1-15\%\right)=\frac{1}{3}\)
\(x.\frac{-280}{3}=\frac{1}{3}\)
\(x=\frac{1}{3}:\frac{-280}{3}\)
\(x=\frac{-1}{280}\)
Vậy \(x=\frac{-1}{280}\)
b)\(\frac{4}{5}x-x-\frac{3}{2}x+\frac{6}{5}=\frac{1}{2}-\frac{4}{3}\)
\(-\frac{17}{10}x+\frac{6}{5}=\frac{-5}{6}\)
\(-\frac{17}{10}x=-\frac{5}{6}-\frac{6}{5}\)
\(-\frac{17}{10}x=\frac{-61}{30}\)
\(x=\frac{-61}{30}:\frac{-17}{10}\)
\(x=\frac{61}{51}\)
Vậy \(x=\frac{61}{51}\)
15 - 3 . (-6) - 2x = 4 . (-2) + 3x - 32
<=> 15 + 18 - 2x = -8 + 3x - 9
<=> -2x - 3x = -15 - 18 - 8 - 9
<=> - 5x = -50
<=> x = 10
Vậy ...
b ) - 8 + 30(x+2)-6(x-5)-24 = 10
<=> - 8 + 30x + 60 - 6x + 30 - 24 = 10
<=> 30x - 6x = 8 - 60 - 30 + 24 + 10
<=> 24x = -48
<=> x = - 2
Vậy ...
b. x^10 = x
x^10 = x^1
x^10 - x^1 = 0
x^1.x^9 - x^1.1 = 0
x^1 . (x^9 - 1 ) = 0
x^1 = 0 hoặc x^9 - 1 = 0
x^1 = 0 = 0^1 x^9 = 0 + 1
=> x = 0 x^9 = 1
x^9 =1^9
=> x = 1
Vậy x = 0 ; 1
=> là suy ra
. là dấu nhân
a, <=> 6x-3-5x-5-4.5=0
<=> x=28
b, 5|3x+1|-4|3x+1|=19
<=> |3x+1|=19
<=>\(\orbr{\begin{cases}3x+1=19\\3x+1=-19\end{cases}}\)
<=>\(\orbr{\begin{cases}x=6\\x=\frac{-20}{3}\end{cases}}\)
Chúc hok tốt!!
1: =>3^x=81
=>x=4
2: =>2^x=8
=>x=3
3: =>x^3=2^3
=>x=2
4: =>x^20-x=0
=>x(x^19-1)=0
=>x=0 hoặc x=1
5: =>2^x=32
=>x=5
6: =>(2x+1)^3=9^3
=>2x+1=9
=>2x=8
=>x=4
7: =>x^3=115
=>\(x=\sqrt[3]{115}\)
8: =>(2x-15)^5-(2x-15)^3=0
=>(2x-15)^3*[(2x-15)^2-1]=0
=>2x-15=0 hoặc (2x-15)^2-1=0
=>2x-15=0 hoặc 2x-15=1 hoặc 2x-15=-1
=>x=15/2 hoặc x=8 hoặc x=7
1. Tìm số tự nhiên x biết:
1) \(3^x.3=243\)
\(3^x=243:3\)
\(3^x=81\)
\(3^x=3^4\)
\(\Rightarrow x=4\)
_____
2) \(7.2^x=56\)
\(2^x=56:7\)
\(2^x=8\)
\(2^x=2^3\)
\(\Rightarrow x=3\)
_____
3) \(x^3=8\)
\(x^3=2^3\)
\(\Rightarrow x=3\)
_____
4) \(x^{20}=x\)
\(x^{20}-x=0\)
\(x\left(x^{19}-1\right)=0\)
\(\Rightarrow x=0\) hoặc \(x=1\)
5) \(2^x-15=17\)
\(2^x=17+15\)
\(2^x=32\)
\(2^x=2^5\)
\(\Rightarrow x=5\)
_____
6) \(\left(2x+1\right)^3=9.81\)
\(\left(2x+1\right)^3=729=9^3\)
\(\rightarrow2x+1=9\)
\(2x=9-1\)
\(2x=8\)
\(x=8:2\)
\(\Rightarrow x=4\)
_____
7) \(x^6:x^3=125\)
\(x^3=125\)
\(x^3=5^3\)
\(\Rightarrow x=5\)
_____
8) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\rightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\)
\(\left(2x-15\right)^3.\left[\left(2x-15\right)^2-1\right]=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{15}{2}\\x=7\\x=8\end{matrix}\right.\)
_____
9) \(3^{x+2}-5.3^x=36\)
\(3^x.\left(3^2-5\right)=36\)
\(3^x.\left(9-5\right)=36\)
\(3^x.4=36\)
\(3^x=36:4\)
\(3^x=9\)
\(3^x=3^2\)
\(\Rightarrow x=2\)
_____
10) \(7.4^{x-1}+4^{x+1}=23\)
\(\rightarrow7.4^{x-1}+4^{x-1}.4^2=23\)
\(4^{x-1}.\left(7+4^2\right)=23\)
\(4^{x-1}.\left(7+16\right)=23\)
\(4^{x-1}.23=23\)
\(4^{x-1}=23:23\)
\(4^{x-1}=1\)
\(4^{x-1}=4^1\)
\(\rightarrow x-1=0\)
\(x=0+1\)
\(\Rightarrow x=1\)
Chúc bạn học tốt
a) x+30%x=-1.31
=> 100%x+30%x=-1.31
=>x.(100%+30%)=-1.31
=>x.13/10=-1.31=-1.31:13/10=-131/130
b) (x-1/2):1/3+5/7=9+5/7
=>(x-1/2).3+5/7=68/7
=>(x-1/2).3=68/7-5/7=9
=>x-1/2=9:3=3
=>x=3+1/2=3 1/2( hỗn số)
c) 1/2x-3/4=14/9.3/7
=>1/2x-3/4=2/3
=>1/2x=2/3+3/4=17/12
x=17/12:1/2=17/12.2=17/6
d) - 5/6 -x = 7/12+ -1/3
=>- 5/6 -x = 7/12+ -4/12=1/4
=> x = -5/6 -1/4=-13/12
e) x + 3/-15 = 1/3
=> x= 1/3 - -3/15 =1/3+3/15
=> x=5/15 + 3/15=8/15
f) (4,5 -2 x). (-1 4/7)=11/14
=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6
=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3
=>x= -19/3: -2x=19/6
Chúc bn thi HKII tốt!!!
a, ( 1+x )^3 = (2x)^3
b, ( x-1 )^2=16
c, (x+1)^2=25
d, 4x^3+15=47
e,(2x-1)^5=x^5
Mn giải nhanh giúp mk vs
a,\(\left(1+x\right)^3=\left(2x\right)^3\)
=>\(1+x=2x\)
=>\(x-2x=-1\)
=>\(-x=-1\)
=>\(x=1\)
vậy \(x=1\)
b,\(\left(x-1\right)^2=16\)
=>\(\left(x-1\right)^2=4^2\)
=>\(x-1=4\)
=>\(x=4+1\)
=>\(x=5\)
Vậy\(x=5\)
c,\(\left(x+1\right)^2=25\)
=>\(\left(x+1\right)^2=5^2\)
=>\(x+1=5\)
=>\(x=5-1\)
=>\(x=4\)
Vậy \(x=4\)
d,\(4x^3+15=47\)
=>\(4x^3=47-15\)
=>\(4x^3=32\)
=>\(x^3=32:4\)
=>\(x^3=8\)
=>\(x^3=2^3\)
=>\(x=2\)
Vậy\(x=2\)
e,\(\left(2x-1\right)^5=x^5\)
=>\(2x-1=x\)
=>\(2x-x=1\)
=>\(x=1\)
Vậy\(x=1\)
ĐÚNG K MÌNH NHA
=> 2x-15 = 1 hoặc 0
=> x=8 (x là số tự nhiên)
b) => x-5 = 0 ; 1 hoặc -1
=> x = 5 ; 6 hoặc 4
a/(x-5)^4=9x-5)^6\(\Rightarrow\) TH1:x-5=1\(\rightarrow\) x=6
\(\Rightarrow\) TH2:x-5=-1\(\rightarrow\) x=4
\(\Rightarrow\) TH3:x-5=0\(\rightarrow\) x=5
vậy....................
b/(2x-15)^5=(2x-15)^6\(\Rightarrow\) 2x-15=1\(\rightarrow\) 2x=16\(\rightarrow\)x=8
\(\Rightarrow\) 2x-15=0\(\rightarrow\)2x=15\(\rightarrow\)x=7.5
vậy................
a) Có : ( x-5 ) \(^4\) = ( x - 5 ) \(^6\)
\(\Rightarrow\left(x-5\right)^6:\left(x-5\right)^4=1\Rightarrow\left(x-5\right)^2=1\)
\(\Rightarrow x-5=1\) hoặc \(x-5=-1\)
\(\Rightarrow x=1+5\) hoặc \(x=-1+5\)
\(\Rightarrow x=6\) hoặc \(x=4\)
b) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\Rightarrow\left(2x-15\right)^5:\left(2x-15\right)^3=1\Rightarrow\left(2x-15\right)^2=1\)
\(\Rightarrow2x-15=1\) hoặc \(2x-15=-1\)
\(\Rightarrow2x=16\) hoặc \(2x=14\)
\(\Rightarrow x=8\) hoặc \(x=7\)