Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
b)\(\left(x-8\right)\left(x-2\right)=0\Leftrightarrow\orbr{\begin{cases}x-8=0\\x-2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=8\\x=2\end{cases}}\)
c) \(\left(x+1\right)+\left(x+2\right)+...+\left(x+10\right)=9x+200\)
\(\Leftrightarrow\left(x+x+...+x\right)+\left(1+2+...+10\right)=9x+200\) (10 số hạng x)
\(\Leftrightarrow10x+55=9x+200\Leftrightarrow x+55=200\)
\(\Leftrightarrow x=145\)
1/51+1/52+1/53+....+1/100>1/100+1/100+1/100+...+1/100(50 so 0)=50/100=1/2
\(\frac{2}{5}.\frac{1}{x}+\frac{1}{x}.2+\frac{2}{5}=0,5\)
\(\Rightarrow\frac{2}{5x}+\frac{2}{x}+\frac{2}{5}=\frac{1}{2}\)
\(\Rightarrow2.\left(\frac{1}{5x}+\frac{1}{x}+\frac{1}{5}\right)=\frac{1}{2}\)
\(\Rightarrow\frac{1}{5x}+\frac{5}{5x}+\frac{x}{5x}=\frac{1}{2}:2=\frac{1}{4}\)
\(\Rightarrow\frac{1+5+x}{5x}=\frac{1}{4}\)
\(\Rightarrow4.\left(1+5+x\right)=5x\)
\(\Rightarrow4+20+4x=5x\)
\(\Rightarrow24+4x=5x\)
\(\Rightarrow5x-4x=24\)
\(\Rightarrow x=24\)
\(150-5\left(x-2\right)^2=25\)
\(5\left(x-2\right)^2=150-25=125\)
\(\left(x-2\right)^2=125:5=25\)
\(\Rightarrow\orbr{\begin{cases}x-2=5\\x-2=-5\end{cases}\Rightarrow\orbr{\begin{cases}x=7\\x=-3\end{cases}}}\)
\(P=\frac{3}{4}\cdot\frac{8}{9}\cdot\frac{15}{16}\cdot\cdot\cdot\frac{99}{100}\)
\(P=\frac{1\cdot3}{2\cdot2}\cdot\frac{2\cdot4}{3\cdot3}\cdot\frac{3\cdot5}{4\cdot4}\cdot\cdot\cdot\frac{9\cdot11}{10\cdot10}\)
\(P=\frac{1\cdot3\cdot2\cdot4\cdot3\cdot5\cdot\cdot\cdot9\cdot11}{2\cdot2\cdot3\cdot3\cdot4\cdot4\cdot\cdot\cdot10\cdot10}\)
\(P=\frac{\left(1\cdot2\cdot3\cdot\cdot\cdot9\right)\cdot\left(3\cdot4\cdot5\cdot\cdot\cdot11\right)}{\left(2\cdot3\cdot4\cdot\cdot\cdot10\right)\cdot\left(2\cdot3\cdot4\cdot\cdot\cdot10\right)}\)
\(P=\frac{1\cdot11}{10\cdot2}=\frac{11}{20}\)
6\(^2\)+ 64 : ( x - 1 ) = 52
36 + 64 : ( x - 1 ) =52
64 ; ( x - 1 ) =64 : 52
x - 1 = \(\frac{16}{13}\)
x = \(\frac{16}{13}\)+1
x = \(\frac{29}{13}\)
HT
a) 3\(^x\) . 3 = 243
3\(^x\) = 81
3\(^x\) = 3\(^4\)
=> = 4
b) 64 . 4\(^x\) = 16\(^8\)
4\(^3\) . 4\(^x\) = 4\(^{16}\)
4\(^{3+x}\) = 4\(^{16}\)
=> 3 + x = 16
x = 13
Học tốt
Đúng thì t cho mk
a) 3^x . 3 = 243
243 = 3^5
3^4 . 3 = 234
nên x = 4
b) 64 . 4^x = 16^8
4^3 . 4^x = ( 4^2)^8
4^3 . 4^x = 4^16
4^(4+x) = 4^16
x = 4^16 : 4^4
x = 4^12
x = 12
a, | x - 3/4 | = 1/2
=>\(\orbr{\begin{cases}x-\frac{3}{4}=\frac{1}{2}\\x-\frac{3}{4}=-\frac{1}{2}\end{cases}}\)
=>\(\orbr{\begin{cases}x=\frac{1}{2}+\frac{3}{4}\\x=-\frac{1}{2}+\frac{3}{4}\end{cases}}\)
=>\(\orbr{\begin{cases}x=\frac{2}{4}+\frac{3}{4}\\x=-\frac{2}{4}+\frac{3}{4}\end{cases}}\)
=>\(\orbr{\begin{cases}x=\frac{5}{4}\\x=\frac{1}{4}\end{cases}}\)
Vậy....
a) \(|x-\frac{3}{4}|=\frac{1}{2}\)
\(< =>\orbr{\begin{cases}x-\frac{3}{4}=\frac{1}{2}\\x-\frac{3}{4}=-\frac{1}{2}\end{cases}}\)
\(< =>\orbr{\begin{cases}x=\frac{1}{2}+\frac{3}{4}\\x=-\frac{1}{2}+\frac{3}{4}\end{cases}}\)
\(< =>\orbr{\begin{cases}x=\frac{5}{4}\\x=\frac{1}{4}\end{cases}}\)
Vay : x = 5/4 hoặc x = 1/4
b)\(saide\)
\(16\cdot4^{x+1}=64\)
\(\Leftrightarrow4^{x+1}=4\)
\(\Leftrightarrow x+1=1\)
\(\Leftrightarrow x=0\)
Ta có: 16 x \(4^{x+1}\)=64
Nên \(4^{x+1}\) =64 : 16 = 4=4\(4^1\)
Suy ra x+1 =1 =>x = 0
hc tot nha