I/ Tìm x
a) ( x - 6 )3 = ( x - 6 )2
b) ( 7 . x - 11 )3 = 25 . 52 + 200
c) 3 + 2x-1 = 24 - [ 42 - ( 22 - 1 ) ]
II/ Tìm x \(\in\)N, biết:
a) 3x . 3 = 243
b) 2x . 162 = 1024
c) 64 . 4x = 168
d) 2x = 16
III/ Viết các kết quả sau dưới dạng một lũy thừa
a) 1255 : 253
b) 276 : 93
c) 420 : 215
d) 24n : 22n
e) 644 . 165 : 420
g) 324 : 86
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Help với!!! Mik cần gấp lắm mai phải nộp rồi ;-;
a) \(\left(x-6\right)^3=\left(x-6\right)^2\Leftrightarrow\orbr{\begin{cases}x-6=1\Leftrightarrow x=7\\x-6=0\Leftrightarrow x=6\end{cases}}\)
b) \(\left(7.x-11\right)^3=2^5.5^2+200\)
\(\Leftrightarrow\left(7.x-11\right)^3=800+200\)
\(\Leftrightarrow\left(7.x-11\right)^3=1000\)
\(\Leftrightarrow\left(7.x-11\right)^3=10^3\)
\(\Leftrightarrow7x-11=10\Leftrightarrow7x=21\Leftrightarrow x=3\)
c) \(3+2^{x-1}=24-\left[4^2-\left(2^2-1\right)\right]\)
\(\Leftrightarrow3+2^{x-1}=24-\left[4^2-3\right]\)
\(\Leftrightarrow3+2^{x-1}=24-13\)
\(\Leftrightarrow3+2^{x-1}=11\)
\(\Leftrightarrow2^{x-1}=8\Leftrightarrow2^{x-1}=2^3\Leftrightarrow x-1=3\Leftrightarrow x=4\)
a)\(3^x.3=243\Leftrightarrow3^x=81\Leftrightarrow3^x=3^4\Leftrightarrow x=4\)
b) \(2^x.16^2=1024\Leftrightarrow2^x.256=1024\Leftrightarrow2^x=4\Leftrightarrow2^x=2^2\Leftrightarrow x=2\)
c) \(64:4^x=16^8\Leftrightarrow4^x=67108864\Leftrightarrow4^x=4^{13}\Leftrightarrow x=13\)
d) \(2^x=16\Leftrightarrow2^x=2^4\Leftrightarrow x=4\)