Question

1)tìm x,biết:
a)(x-1)^3=343
b)(x-2)^4=4096
 

Answer 1

a ) ( x - 1 )³ = 343

7³ = 343

x + 1 = 7

x = 7 - 1

x = 6

b ) ( x - 2 )⁴ = 4096

8⁴ = 4096

x - 2 = 8

x = 8 + 2

x = 10

Answer 2

\(\left(x-1\right)^3=343=7^3\) => x -1 =7 => x =8

\(\left(x-2\right)^4=4096=8^4=\left(-8\right)^4\)\(\Rightarrow\orbr{\begin{cases}x-2=8\\x-2=-8\end{cases}\Rightarrow\orbr{\begin{cases}x=10\\x=-6\end{cases}}}\)

Answer 3

a) \(\left(x-1\right)^3=343\)

\(\left(x-1\right)=7^3\)

  \(x-1=7\)

  \(x=7+1\)        

  \(x=8\)

b) \(\left(x-2\right)^4=4094\)

    \(\left(x-2\right)^4=8^4\)

      \(x-2=8\) hoặc \(x-2=-8\)

      \(x=8+2\)         \(x=-8+2\)

      \(x=10\)               \(x=-6\)

Vậy \(x=10\) hoặc \(x=-6\)