Question

(x - 4)²=9

(2x - 1)³=8

Answer 1

a) \(\left(x-4\right)^2=9\)

\(\Leftrightarrow\left[\begin{matrix}x-4=3\\x-4=-3\end{matrix}\right.\)

\(\Leftrightarrow\left[\begin{matrix}x=7\\x=-1\end{matrix}\right.\)

b) \(\left(2x-1\right)^3=8\)

\(\Leftrightarrow2x-1=\sqrt[3]{8}=2\)

\(\Leftrightarrow x=1,5\)

Answer 2

a/ (x - 4)² = 9

=> (x - 4)² = 3²

hoặc (x - 4)² = (-3)²

+) x - 4 = 3

=> x = 3 + 4 = 7

+) x - 4 = -3

=> x = -3 + 4 = 1

Vậy x = 7 hoặc x = -1

b/ (2x - 1)³ = 8

=> (2x - 1)³ = 2³

=> 2x - 1 = 2

=> 2x = 2 + 1 = 3

=> x = \(\frac{3}{2}\)

Vậy x = \(\frac{3}{2}\)

Answer 3

1) \(\left(x-4\right)^2=9\)

=>\(\left[\begin{matrix}x-4=3\\x-4=-3\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=7\\x=1\end{matrix}\right.\)

Vậy....

2)\(\left(2x-1\right)^3=8\)

=> 2x-1=2

=>2x=3

=>x=3/2