a) \(2^x.4=128\)<=>\(2^{x+2}=2^7\)=> x+2=7=>x=5
b) \(x^{15}=x^1\)<=> \(x^{15}-x=x\left(x^{14}-1\right)=0\)
<=> \(\left[\begin{array}{nghiempt}x=0\\x^{14}-1=0\end{array}\right.\)<=> \(\left[\begin{array}{nghiempt}x=0\\x=-1,x=1\end{array}\right.\)
vậy x={-1,0,1}
c) \(\left(2x+1\right)^3=125\)<=> \(\left(2x+1\right)^3=5^3\)=> 2x+1=5<=> x=2
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