Question

[Nguyễn Kim Ngân]

tìm x

(x + 1) mũ 3 = 125

2 mũ x + 2 mũ x +3 ( số 3 là số mũ) =576

Answer 1

[Võ Đông Anh Tuấn]

\(\left(x+1\right)^3=125\)

\(\left(x+1\right)^3=\sqrt[3]{125}\)

\(\left(x+1\right)=5\)

\(x=5-1\)

\(x=4\)

\(2^x+2^{x+3}=576\)

\(2^x\left(1+2^3\right)=576\)

\(2^x=576:9\)

\(2^x=64\)

\(2^x=2^6\)

\(\Rightarrow x=6\)

Answer 2

[Hà Phương]

\(2^x+2^{x+3}=576\)

\(\Rightarrow2^x+2^x.2^3=24^2\)

\(\Rightarrow2^x\left(1+2^3\right)=24^2\)

\(\Rightarrow2^x+3^2=24^2\)

\(\Rightarrow2^x=\left(24:3\right)^2\)

\(\Rightarrow2^x=8^2\)

\(\Rightarrow2^x=\left(2^3\right)^2\)

\(\Rightarrow2^x=2^6\)

\(\Rightarrow x=6\)