Question

bài 50: tìm x biết:

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

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

Answer 1

a)
x(x - 2) + x - 2 = 0
Tương đương (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 = 1/5.
Vậy x = 1/5; x = 3.

Answer 2

\(a,\left(x+1\right)\left(x-2\right)=0\\ \left[{}\begin{matrix}x+1=0\\x-2=0\end{matrix}\right.=>x=-1;x=2\\ b,5x\left(x-3\right)-\left(x-3\right)=0\\ \left(5x-1\right)\left(x-3\right)=0\\ \left[{}\begin{matrix}5x-1=0\\x-3=0\end{matrix}\right.=>x=\dfrac{1}{5};x=3\)

Answer 3

`a, (x+1)(x-2) = 0`

`->` \(\left[{}\begin{matrix}x-2=0\\x+1=0\end{matrix}\right.\)

`->` \(\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\)

`b, (5x-1)(x-3) = 0`

`->` \(\left[{}\begin{matrix}5x-1=0\\x-3=0\end{matrix}\right.\)

`->` \(\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=3\end{matrix}\right.\)