Question

Tính x, biết :

a) \(x\left(x-2\right)+x-2=0\)

b) \(5x\left(x-3\right)-x+3=0\)

Answer 1

Bài giải:

a) x(x - 2) + x - 2 = 0

(x - 2)(x + 1) = 0

Hoặc x - 2 = 0 => x = 2

Hoặc x + 1 = 0 => x = -1

Vậy x = -1; x = 2

b) 5x(x - 3) - x + 3 = 0

5x(x - 3) - (x - 3) = 0

(x - 3)(5x - 1) = 0

Hoặc x - 3 = 0 => x = 3

Hoặc 5x - 1 = 0 => x = $\frac{1}{5}$.

Vậy x = $\frac{1}{5}$; x = 3.

Answer 2

a) x (x - 2) + x - 2 = 0

(x - 2) (x + 1) = 0

\(\Rightarrow\) x - 2 = 0 hoặc x + 1 = 0

\(\Rightarrow\) x = 2 \(\Rightarrow\) x = -1

Vậy x = 2 , x = -1

b) 5x (x - 3) - x + 3 = 0

5x (x - 3) - (x - 3 ) = 0

(x - 3) (5x -1) =0

\(\Rightarrow\) x - 3 = 0 hoặc 5x - 1 = 0

\(\Rightarrow\) x = 3 \(\Rightarrow\) x = \(\dfrac{1}{5}\)

Vậy x = 3 , x = \(\dfrac{1}{5}\)

Answer 3

a) \(x(x-2) + x - 2 = 0\)

\(\left(x-2\right)\left(x+1\right)=0\)

\(\Leftrightarrow x-2=0\) \(\Rightarrow x=2\)

Hoặc \(x+1 = 0\) \(\Rightarrow x=-1\)

Vậy \(x= 2\) , \(x = -1\)

b) \(5x(x-3) - x+3 = 0\)

\(5x(x-3) - (x-3) = 0\)

\((x-3) (5x - 1) = 0\)

\(\Leftrightarrow x-3=0\Rightarrow x=3\)

Hoặc \(5x - 1 = 0\) \(\Rightarrow5x=1\Rightarrow x=\dfrac{1}{5}\)

Vậy \(x=3 \) , \(x=\dfrac{1}{5}\)