Question

(2x-1)^3 bằng -27

Answer 1

\(\left(2x-1\right)^3=-27\)

\(\left(2x-1\right)^3=\left(-3\right)^3\)

\(\Rightarrow2x-1=-3\)

\(\Rightarrow2x=-3+1\)

\(2x=-2\)

\(x=-2:2\)

\(x=-1\)

Vậy x = - 1

Answer 2

\(\left(2x-1\right)^3=27\)

\(\Leftrightarrow\left(2x-3\right)=\sqrt[3]{27}\)

\(\Leftrightarrow\left(2x-3\right)=3\)

\(\Leftrightarrow2x=6\)

\(\Leftrightarrow x=3\)

Answer 3

(2x-1)^3=-27; -27=(-3)^3

nên 2x-1=-3

       2x =-2

       x   =-1

 

Answer 4

\(\left(2x-1\right)^3=27\)

\(\left(2x-1\right)^3=3^3\)

\(\Rightarrow2x-1=3\)

\(2x=3+1\)

\(2x=4\)

\(x=4:2\)

\(x=2\)

Vậy \(x=2\)

Answer 5

( 2x - 1 )^3 = -27

( 2x - 1 )^3 = ( -3 )^3

=> 2x - 1    = -3

=> 2x         = -3 + 1

  2x             = -2

  x               = -2 : 2

  x               = -1

Vậy   x = -1