Bài 42:
a) \(x=\dfrac{1}{2}\)
b) \(x\text{-}2=1\Rightarrow x=3\)
\(x\text{-}2=\text{-}1\Rightarrow x=1\)
c) \(\left(2x\text{-}1\right)^3=\left(\text{-}2\right)^3\Rightarrow2x\text{-}1=\text{-}2\Rightarrow2x=\text{-}1\Rightarrow x=\text{-}\dfrac{1}{2}\)
d) \(x+\dfrac{1}{2}=\dfrac{1}{4}\Rightarrow x=\text{-}\dfrac{1}{4}\)
\(x+\dfrac{1}{2}=\text{-}\dfrac{1}{4}\Rightarrow x=\text{-}\dfrac{3}{4}\)
Bài 43 :
2225 = (23)75 = 875
3150 = (32)75 = 975
Vì 875 < 975 nên 2225 < 3150
Bài 44 :
a) 54
b) \(\left(\dfrac{3}{7}\right)^9\)
c) \(2\dfrac{1}{8}\)
Bài 45 :
a) \(3^3\)
b) \(2^8\)
c) \(2^7\)
d) \(3^1\)
Bài 46 :
a) \(2^5\ge2^n>2^2\Rightarrow2< n\le5\Rightarrow n\in\left\{3;4;5\right\}\)
b) \(3^5\le3^n\le3^5\Rightarrow n=5\)
Bài 47 :
\(8^7\text{-}2^{18}=\left(2^3\right)^7\text{-}2^{18}=2^{17}.\left(2^4\text{-}2\right)=2^{17}.14⋮14\)
sách bài tập dễ thì tự làm đi,ko thì hỏi bác gg cũng đầy à