Question

[Vân Anh]

a) ( x - 5 )² - 18 = 46

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b)  2¹⁵ ( x + 3 )  = 2^{18  -}  2¹⁷

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^{mấy bạn giải ghi rõ cách làm, phân tích  hộ mình nha!!! Thanks}

Answer 1

[Tô Hoài An]

a) \(\left(x-5\right)^2-18=46\)

\(\left(x-5\right)^2=46+18\)

\(\left(x-5\right)^2=64\)

\(\Rightarrow\left(x-5\right)^2=8^2\)hoặc \(\left(x-5\right)^2=\left(-8\right)^2\)

             \(x-5=8\)                   \(x-5=-8\)

      \(x=8+5=13\)          \(x=-8+5=-3\)

Vậy \(x=13\)hoặc \(x=-3\)

Answer 2

[nguyễn minh anh]

a)\(\left(x-5\right)^2-18=46\Rightarrow\left(x-5\right)^2=64\)

\(\Rightarrow\orbr{\begin{cases}x-5=8\\x-5=-8\end{cases}\Rightarrow\orbr{\begin{cases}x=13\\x=-3\end{cases}}}\)

b)\(2^{15}\left(x+3\right)=2^{18}-2^{17}\Rightarrow2^{15}\left(x+3\right)=2^{17}\left(2-1\right)=2^{17}\)

\(\Rightarrow x+3=2^{17}:2^{15}=2^{17-15}=2^2\Rightarrow x=1\)