Question

Tìm x : 

a) x(x - 4 ) - ( x^2 - 8 ) = 0

Answer 1

a. x.(x - 4) - (x² - 8) = 0

<=> x² - 4x - x² + 8 = 0

<=> 8 - 4x = 0

<=> 4x = 8

<=> x = 2

Vậy x = 2.

Answer 2

a ) \(x\left(x-4\right)-\left(x^2-8\right)=0\)

\(\Leftrightarrow x^2-4x-\left(x^2-8\right)=0\)

\(\Leftrightarrow x^2-4x-x^2+8=0\)

\(\Leftrightarrow-4x+8=0\)

\(\Rightarrow-4x=-8\)

\(\Leftrightarrow x=-2\)

Answer 3

\(x\left(x-4\right)-\left(x^2-8\right)=0\)

\(\Rightarrow x^2-4x-x^2+8=0\)

\(\Rightarrow\left(x^2-x^2\right)-4x=0-8\)

\(\Rightarrow-4x=-8\)

\(\Rightarrow x=\left(-8\right):\left(-4\right)\)

\(\Rightarrow x=2\)

Vậy x = 2