Tìm x , y :
a , \(\frac{2}{3}.3^{x+1}-7.3^x=-405\)
b , \(\left(0,4x-1,3\right)^2=5,29\)
c , \(5.2^{x+1}.2^{-2}-2^x=384\)
d , \(3^{x+2}.5^y=45^x\)
e , \(4^x+4^{x+3}=4160\)
f , \(2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
Tìm x , y:
a , \(\dfrac{2}{3}.3^{x+1}-7.3^x=405\)
b , \(\left(0,4x-1,3\right)^2=5,29\)
c , \(5.2^{x+1}.2^{-2}-2^x=384\)
d , \(4^x+4^{x+3}=4160\)
e , \(2^{x-1}+5.2^{x-2}=\dfrac{7}{32}\)
a: \(\Leftrightarrow3^x\cdot\left(\dfrac{2}{3}\cdot3-7\right)=405\)
\(\Leftrightarrow3^x=-81\)(vô lý)
b: \(\left(0,4x-1,3\right)^2=5,29\)
=>0,4x-1,3=2,3 hoặc 0,4x-1,3=-2,3
=>0,4x=3,6 hoặc 0,4x=-1
=>x=9 hoặc x=-2,5
c: \(5\cdot2^{x+1}\cdot2^{-2}-2^x=284\)
\(\Leftrightarrow2^x\cdot5\cdot2\cdot2^{-2}-2^x=284\)
\(\Leftrightarrow2^x\cdot\left(\dfrac{5}{2}-1\right)=284\)
\(\Leftrightarrow2^x=\dfrac{568}{3}\)(vô lý)
d: \(\Leftrightarrow4^x\left(1+4^3\right)=4160\)
\(\Leftrightarrow4^x=64\)
hay x=3
Tìm x, y biết:
a) \(2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
b) (3-x) : 0,16 = -9 : (x-3)
c) \(\left(3x-\frac{4}{5}\right)^2+\left(2y+\frac{3}{7}\right)^2=0\)
d) \(\left(x+y-\frac{1}{2}\right)^2+\left(x-y+\frac{1}{6}\right)^2=0\)
e) x. \(\left(x-\frac{1}{4}\right)\)> 0
tìm x,biết:
a) \(4^x+4^{x+3}=4160\)
b)\(2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
b)\(2^{x-1}+5\cdot2^{x-2}=\frac{7}{32}\)
\(2^x:2+5\cdot2^x:2^2=\frac{7}{32}\)
\(2^x:2+2^x:\frac{4}{5}=\frac{7}{32}\)
\(2^x\cdot\left(\frac{1}{2}+\frac{5}{4}\right)=\frac{7}{32}\)
\(2^x\cdot\frac{7}{4}=\frac{7}{32}\)
\(2^x=\frac{7}{32}:\frac{7}{4}=\frac{1}{8}\)
\(2^x=\frac{2^0}{2^3}=2^{-3}\)
\(\Rightarrow x=-3\)
a) \(4^x+4^{x+3}=4160\)
\(\Rightarrow4^x+4^x.4^3=4160\)
\(\Rightarrow4^x.\left(1+4^3\right)=4160\)
\(\Rightarrow4^x.65=4160\)
\(\Rightarrow4^x=64\)
\(\Rightarrow4^x=4^4\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
b) \(2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
\(\Rightarrow2^x.\frac{1}{2}+5.2^x.\frac{1}{4}=\frac{7}{32}\)
\(\Rightarrow2^x.\left(\frac{1}{2}+5.\frac{1}{4}\right)=\frac{7}{32}\)
\(\Rightarrow2^x.\frac{7}{4}=\frac{7}{32}\)
\(\Rightarrow2^x=\frac{7}{32}:\frac{7}{4}\)
\(\Rightarrow2^x=\frac{1}{8}\)
\(\Rightarrow2^x=2^{-3}\)
\(\Rightarrow x=-3\)
Vậy \(x=-3\)
a)\(4^x+4^{x+3}=4160\)
\(4^x+4^x\cdot4^3=4160\)
\(4^x\left(1+4^3\right)=4160\)
\(4^x\cdot65=4160\)
\(4^x=4160:65=64\)
\(4^x=4^3\)
\(\Rightarrow x=3\)
Tìm x biết
a) \(\frac{x+1}{2}+\frac{x+1}{3}+\frac{x+1}{4}=\frac{x+1}{5}+\frac{x+1}{6}\)
b) 42 + 4x+3 = 4160
c) 2x-1 + 5.2x-2 = \(\frac{7}{32}\)
Tìm x thuộc N:
a) 4^x+a^x+3 = 4160
b) 2^x-1+5.2^x-2 = 7/32
1. So sánh:
a. 1 và \(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+.....+\frac{1}{2^{50}}\)
b. \(\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+.....+\frac{1}{3^{100}}\)với \(\frac{1}{2}\)
c. \(\frac{1}{4}+\frac{1}{4^2}+\frac{1}{4^6}+.....\frac{1}{4^{1000}}\)với \(\frac{1}{3}\)
2. Tìm x, biết:
a.\(\left(\frac{2}{5}-x\right):1\frac{1}{3}+\frac{1}{2}=-4\)
b.\(3-\frac{1-\frac{1}{2}}{1+\frac{1}{x}}=2\frac{2}{3}\)
c.\(4^x+4^{x+3}=4160\)
d.\(2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
e.\(\frac{x-100}{24}+\frac{x-98}{26}+\frac{x-96}{24}=3\)
g.\(\frac{x-1}{65}+\frac{x-3}{63}+=\frac{x-5}{61}+\frac{x-7}{59}\)
tìm x, y
\(a.\left(x-5\right)^2=\left(1-3x\right)^2\)
\(b.\left(x+5\right)^2+\left(3y-9\right)^4=0\)
\(c.\frac{1}{8}.16^x=2^x\)
\(d.2^{x-1}+5.2^{x-2}=\frac{7}{32}\)
\(a,\left(x-5\right)^2=\left(1-3x\right)^2\)
\(\Rightarrow\left(x-5\right)^2-\left(1-3x\right)^2=0\)
\(\Rightarrow\left(x-5+1-3x\right)\left(x-5-1+3x\right)=0\)
\(\Rightarrow\left(-2x-4\right)\left(4x-6\right)=0\)
\(\Rightarrow\left(x+2\right)\left(2x-3\right)=0\)
\(\Rightarrow\hept{\begin{cases}x+2=0\\2x-3=0\end{cases}\Rightarrow\hept{\begin{cases}x=-2\\x=\frac{3}{2}\end{cases}}}\)
a) \(\left(x-5\right)^2=\left(1-3x\right)^2\)
\(\Rightarrow x-5=1-3x\)
\(\Leftrightarrow x+3x=1+5\)
\(\Leftrightarrow4x=6\)
\(\Leftrightarrow x=\frac{3}{2}\)
Tìm các số nguyên tố x và y biết:
a) \(5.2^{x+1}.2^{-2}-2^x=384\)
b) \(3^{x+2}.5^y=45^x\)
c) \(\left(x+1\right)^{x+1}=\left(x+1\right)^{x+1}\)
d) \(27< 3^x< 243\)
a) \(5.2^{x+1}.2^{-2}-2^x=384\Leftrightarrow2^x\left(5.2^{-2}.2-1\right)=384\)\(\Leftrightarrow2^x.1,5=384\Leftrightarrow2^x=384:1,5=256=2^8\)
\(\Rightarrow x=8\)
b) \(3^{x+2}.5^y=45^x\Leftrightarrow3^{x+2}.5^y=3^{2x}.5^x\Leftrightarrow\frac{3^{2x}}{3^{x+2}}=\frac{5^y}{5^x}\)\(\Leftrightarrow3^{2x-x+2}=5^{y-x}\Leftrightarrow3^{x+2}=5^{y-x}\)
\(\Rightarrow x+2=y-x=0\Rightarrow x=y=-2\)
Tìm x,y \(\in\)Z:
\(a,5.2^{x+1}.2^{-2}-2^x=384\)
\(b,3^{x+2}.5^y=45^x\)
\(c,\left(x+1\right)^{x+1}=\left(x+1\right)^{x+3}\)
#Ai đúng mình tặng 3 tick nha! Mình đang cần gấp
a) \(5.2^{x+1}.2^{-2}-2^x=384\)
\(\Leftrightarrow2^x.2.\frac{5}{4}-2^x=384\)
\(\Leftrightarrow2^x.\left(\frac{5}{2}-1\right)=384\)
\(\Leftrightarrow2^x.\frac{3}{2}=384\)
\(\Leftrightarrow2^x=256\)
\(\Leftrightarrow2^x=2^8\)
\(\Leftrightarrow x=8\)
c) \(\left(x+1\right)^{x+1}=\left(x+1\right)^{x+3}\)
\(\Leftrightarrow\left(x+1\right)^{x+3}-\left(x+1\right)^{x+1}=0\)
\(\Leftrightarrow\left(x+1\right)^{x+1}\left[\left(x+1\right)^2-1\right]=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(x+1\right)^{x+1}=0\\\left(x+1\right)^2-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x+1=0\\\left(x+1\right)^2=1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-1\\x\in\left\{0;-2\right\}\end{cases}}}\)
Vậy \(x\in\left\{0;-1;-2\right\}\)