Question

8x^3-27=0

Tìm x hộ tớ nhé

Answer 1

\(8x^3-27=0\)

\(\Leftrightarrow8x^3=27\)

\(\Leftrightarrow x^3=\frac{27}{8}\)

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

Answer 2

8x³-27=0

8x³=27

x³=27/8

x³=(3/2)³

x=3/2

Answer 3

bạn đc học 7 hàng đẳng thức đáng nhớ chưa

Answer 4

8x³ - 27 =0

8x³ = 27

x³ = 27/8

x³ = ( 3/2 )³

=> x = 3/2

Answer 5

\(8x^3-27=0\)

\(\Rightarrow\left(2x\right)^3-3^3=0\)

\(\Rightarrow\left(2x-3\right)\left(4x^2+6x+9\right)=0\)

\(\Rightarrow\orbr{\begin{cases}2x-3=0\\4x^2+6x+9=0\end{cases}}\)

TH1 : \(2x-3=0\Rightarrow x=\frac{3}{2}\)

Th2 : \(4x^2+6x+9=0\)

\(\Rightarrow\left(2x\right)^2+2.2x.\frac{3}{2}+\frac{9}{4}-\frac{9}{4}+9=0\)

\(\Rightarrow\left(2x+\frac{3}{2}\right)^2+\frac{27}{4}=0\left(ktm\right)\)

Vậy \(x=\frac{3}{2}\)

Answer 6

8x³ - 27 = 0
\(\Leftrightarrow\)(2x)³ - 3³ = 0 
\(\Leftrightarrow\)( 2x - 3 ) ( 2x + 6x + 3 ) = 0

\(\Rightarrow\)\(\hept{\begin{cases}2x-3=0\\8x+3=0\end{cases}}\Rightarrow\orbr{\begin{cases}2x=3\\8x=-3\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{-3}{8}\end{cases}}\)