tim x
(x-3):[\(\frac{1}{2}\)nhan (-1\(\frac{3}{4}\)) ] = -2\(\frac{1}{2}\)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\frac{27^5}{81^3}=\frac{\left(3^3\right)^5}{\left(3^4\right)^3}=\frac{3^{15}}{3^{12}}=3^3=27\)
_Minh ngụy_
2.(x + 3) = 23 . 32
=> 2.(x + 3) = 8.9
=> 2.(x + 3) = 72
=> x + 3 = 72 : 2
=> x + 3 = 36
=> x = 36 - 3
=> x = 33
Chúc bạn học tốt !!!!!
\(2x+3=2^3+3^2\)
\(\Leftrightarrow2x+3=8+9\)
\(\Leftrightarrow2x+3=17\)
\(\Leftrightarrow2x=17-3\)
\(\Leftrightarrow2x=14\)
\(\Leftrightarrow x=7\)
_Hắc phong_
a) 2x = 64
=> 2x = 26
=> x = 6
b) 5x = 7x
=> 7x - 5x = 0
=> 5x(2x - 1) = 0
=> \(\orbr{\begin{cases}5^x=0\\2^x-1=0\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x\in\varnothing\\2^x=1\end{cases}}\)\(\Rightarrow2^x=2^0\Rightarrow x=0\)
c) 5x . 53 = 125
=> 5x + 3 = 53
=> x + 3 = 3
=> x = 0
d) 3x - 17 = 64
=> 3x = 64 + 17
=> 3x = 81
=> 3x = 34
=> x = 4
e) (3x - 5)3 = 52 . 24 + 600
=> (3x - 5)3 = 25.16 + 600
=> (3x - 5)3 = 400+ 600
=> (3x - 5)3 = 1000
=> (3x - 5)3 = 103
=> 3x - 5 = 10
=> 3x = 15
=> x = 15 : 3
=> x = 5
g) (5x - 15)3 = (5x - 15)7
=> (5x - 15)7 - (5x - 15)3 = 0
=> (5x - 15)3. [(5x - 15)4 - 1] = 0
=> \(\orbr{\begin{cases}\left(5x-15\right)^3=0\\\left(5x-15\right)^4-1=0\end{cases}\Rightarrow\orbr{\begin{cases}\left(5x-15\right)=0\\\left(5x-15\right)^4=1\end{cases}\Rightarrow}\orbr{\begin{cases}5x-15=0\\5x-15=\pm1\end{cases}}}\)
Nếu 5x - 15 =0
=> 5x = 15
=> x = 3
Nếu 5x - 15 = 1
=> 5x = 16
=> x = 16 : 5
=> x = 16/5
Nếu 5x - 16 = -1
=> 5x = 14
=> x = 14 : 5
=> x = 14/5
Vậy \(x\in\left\{3;\frac{16}{5};\frac{14}{5}\right\}\)
a) 2x = 64
Vì 26 = 64 nên x = 6
Vậy x = 6
b) 5x = 7x
Vì 50 = 1 và 70 = 1
=> x = 0
Vậy, x = 0
c) 5x . 53 = 625
Ta có 625 = 54
nên 5x . 53 = 54
5x+3 = 54
=> x = 1
Vậy x = 1
d) 3x - 17 = 64
3x = 64 + 17 = 81 = 34
=> x = 4
Vậy x = 4
e) ( 3x - 5 ) 3 = 52 . 24 + 600
( 3x - 5 ) 3 = 25 . 16 + 600 = 1000 = 103
=> 3x - 5 = 10
3x = 10 + 5 = 15
x = 15 : 3 = 5
Vậy x = 5
g) ( 5x - 15 ) 3 = ( 5x - 15 ) 7
=> (5x - 15 ) 3 : ( 5x - 15 ) 7 = 1
( 5x - 15 ) 3 - 7 = 1
( 5x - 15 ) -4 = 1 = 1-4 = -1-4
=> 5x - 15 = 1 hoặc 5x - 15 = -1
5x = 1 + 15 hoặc 5x = -1 + 15
5x = 16 hoặc 5x = 14
\(x=\frac{16}{5}\) hoặc \(x=\frac{14}{5}\)
Vậy, \(x\in\left\{\frac{16}{5};\frac{14}{5}\right\}\)
Cbht
1256 và 258
1256=125.125.125.125.125.125=53.53.53.53.53.53=53+3+3+3+3+3=518
258=25.25...25(8 chữ số 25)=52.52...52(8 chữ số 52)=52+2+2+2+2+2+2+2=516
Vì 518>516
=> 1256>258
3502 và 275
3502=350.350=2.52.7.2.52.7=22.54.72
275=2.2.2....2(75 chữ số 2)=24.210.26..250
Vì 22.54.72<24.210.26(22<24;54<210;72<26)
=>3502<275
Chúc bạn học tốt!
\(210+\left(y-15\right)\times3=195\)
\(210+\left(y-15\right)=195:3=65\)
\(y-15=210-65=145\)
\(\Rightarrow x=145+15=160\)
Vậy \(x=160\)
120 - 4x(y - 3) = 136
=> 4x(y - 3) = 136 - 120
=> 4x(y - 3) = 16
=> x(y - 3) = 16 : 4
=> x(y - 3) = 4
Mà 4 = 1.4 = 2.2 = (-1).(-4) = (-2).(-2)
Lập bảng xét tất cả 6 trường hợp :
\(x\) | \(1\) | \(4\) | \(2\) | \(-2\) | \(-1\) | \(-4\) |
\(y-3\) | \(4\) | \(1\) | \(2\) | \(-2\) | \(-4\) | \(-1\) |
\(x\) | \(1\) | \(4\) | \(2\) | \(-2\) | \(-1\) | \(-4\) |
\(y\) | \(7\) | \(4\) | \(5\) | \(1\) | \(-1\) | \(2\) |
Vậy các cặp (x,y) thỏa mãn là : (1;7) ; (2;5) ; (4;4) ; (-2 ; 1) ; (-1 ; -1) ; (- 4;2)
120 - 4(y - 3) = 136
<=> -4(y - 3) = 136 - 120
<=> -4(y - 3) = 16
<=> y - 3 = 16 : (-4)
<=> y - 3 = -4
<=> y = -4 + 3
<=> y = -1
=> y = -1
a) \(2^3\cdot4^5=2^3\cdot2^{10}=2^{13}\)
b) \(3^4\cdot27^2=3^4\cdot3^6=3^{10}\)
c) \(16^{10}:8^2=2^{40}:2^6=2^{34}\)
d) \(12^3:3^3=\left(12:3\right)^3=4^3\)
e) \(3^4\cdot2^4=\left(3\cdot2\right)^4=6^4\)
g) \(9^{13}\cdot5^{26}=9^{13}\cdot25^{13}=\left(9\cdot25\right)^{13}=225^{13}\)
=))
\(A=124\left(\frac{1}{1.1985}+\frac{1}{2.1986}+\frac{1}{3.1987}+...+\frac{1}{16.2000}\right)\)
\(=\frac{124}{1984}.\left(1-\frac{1}{1985}+\frac{1}{2}-\frac{1}{1986}+...+\frac{1}{16}-\frac{1}{2000}\right)\)
\(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{16}\right)-\left(\frac{1}{1985}+\frac{1}{1986}+...+\frac{1}{2000}\right)\right]\)
Và \(B=\frac{1}{1.17}+\frac{1}{2.18}+...+\frac{1}{1984.2000}\)
\(=\frac{1}{16}\left[\left(1-\frac{1}{17}+\frac{1}{2}-\frac{1}{18}+...+\frac{1}{1984}-\frac{1}{2000}\right)\right]\)
\(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{1984}\right)-\left(\frac{1}{17}+\frac{1}{18}+...+\frac{1}{2000}\right)\right]\)
= \(\frac{1}{16}\) . \(\left[\left(1+...+\frac{1}{16}\right)+\left(\frac{1}{17}+...+\frac{1}{1984}-\frac{1}{17}-...-\frac{1}{1984}\right)-\left(\frac{1}{1985}+...+\frac{1}{2000}\right)\right]\)
= \(=\frac{1}{16}\left[\left(1+\frac{1}{2}+...+\frac{1}{16}\right)-\left(\frac{1}{1985}+\frac{1}{1986}+...+\frac{1}{2000}\right)\right]\)
Vậy A = B
\(\left(x-3\right):\left[\frac{1}{2}.\left(-1\frac{3}{4}\right)\right]=-2\frac{1}{2}\)
\(\left(x-3\right):\left[\frac{1}{2}.\left(\frac{-7}{4}\right)\right]=\frac{-5}{2}\)
\(\left(x-3\right):\frac{-7}{8}=\frac{-5}{2}\)
\(\left(x-3\right)=\frac{-5}{2}.\frac{-7}{8}\)
\(\left(x-3\right)=\frac{35}{16}\)
\(x=\frac{35}{16}+3=\frac{83}{16}\)
\(\left(x-3\right):\left[\frac{1}{2}.\left(-1\frac{3}{4}\right)\right]=-2\frac{1}{2}\)
\(\left(x-3\right):\left(\frac{1}{2}.\frac{-7}{4}\right)=\frac{-5}{2}\)
\(\left(x-3\right):\frac{-7}{8}=\frac{-5}{2}\)
\(x-3=\frac{-5}{2}.\frac{-7}{8}\)
\(x-3=\frac{35}{16}\)
\(x=\frac{35}{16}+3\)
\(x=\frac{35+48}{16}=\frac{83}{16}\)