Question

(27-x).(x+9)=0

Answer 1

\(\Leftrightarrow\left[{}\begin{matrix}x=27\\x=-9\end{matrix}\right.\)

Answer 2

    \(\left[{}\begin{matrix}27-x=0\\x+9=0\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=27\\x=-9\end{matrix}\right.\)

\(vậy...\)

Answer 3

TH1: 27 - x = 0

=> x = 27

TH2: x + 9 = 0 

=> x = -9

Vậy x = 27 hoặc x = -9

Answer 4

(27-x).(x+9)=0
⇔27-x=0⇒x=27
    x+9=0⇒x=-9
Vậy x=27 hoặc x=-9