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\(\left(\dfrac{-3}{4}\right)^{3x-1}=\dfrac{256}{81}\)
\(\Rightarrow\left(\dfrac{-3}{4}\right)^{3x-1}=\left(\dfrac{4}{3}\right)^4\)
Xem lại đề
a) (1+3x)^4 = 256
=> (1+3x)^4= 4^4
=> 1+3x=4
=> 3x=3
=> x=1
b) \(\frac{3^{15}.29+3^{15}.88}{3^{13}.81}=\frac{3^{15}.\left(29+88\right)}{3^{13}.81}=\frac{3^{15}.117}{3^{13}.81}=\frac{3^2.13}{9}=13\)
\(\left(\frac{-3}{4}\right)^{3x+5}=\left(\frac{81}{256}\right)^{-1}\)
\(\Rightarrow\left(\frac{-3}{4}\right)^{3x+5}=\frac{256}{81}\)
\(\Rightarrow\left(\frac{-3}{4}\right)^{3x+5}=\left(\frac{-3}{4}\right)^{-4}\)
\(\Rightarrow3x+5=-4\)
\(\Rightarrow3x=-9\)
\(\Rightarrow x=-3\)
Vậy x= -3
a.(2x +1). (2x+1)=1
Mà chỉ có 1.1=1
Vậy 2x + 1=1
2x=1-1
2x=0
Suy ra: x= 0
Hoàng Khánh Thi thiếu nha.
a) (2x+1)2 = \(\left(\pm1\right)^2\)
=> 2x + 1 = 1 hoặc 2x + 1 = -1
=> 2x = 0 hoặc 2x = -2
=> x = 0 hoặc x = -1.
e)
\(\left(-\frac{3}{4}\right)^{3x-1}=\frac{256}{81}\)
\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{4}{3}\right)^4\)
\(\left(-\frac{3}{4}\right)^{3x}=\left(-\frac{3}{4}\right)^{-4}\)
\(3x=-4\)
\(x=-\frac{4}{3}\)
f) \(172x^2-7^9:98^3=2^{-3}\)
\(172x^2-\frac{7^9}{\left(7^2.2\right)^3}=\frac{1}{2^3}\)
\(172x^2-\frac{7^3}{2^3}=\frac{1}{2^3}\)
\(172x^2=\frac{7^3}{2^3}+\frac{1}{2^3}=\frac{344}{8}\)
\(x^2=\frac{344}{8}:172=\frac{1}{4}\)
x=1/2 hoặc x=-1/2
1. \(\left(-\frac{3}{4}\right)^{3x-2}=\frac{81}{256}\)
\(\left(\frac{-3}{4}\right)^{3x-2}=\left(\frac{-3}{4}\right)^4\)
=> 3x - 2 = 4
=> 3x = 6
=> x = 2
2. \(\left(\frac{1}{2}\right)^{3x-1}=\frac{1}{32}\)
\(\left(\frac{1}{2}\right)^{3x-1}=\left(\frac{1}{2}\right)^5\)
=> 3x - 1 = 5
=> 3x = 6
=> x = 2
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