Question

Tìm x biết : \(\left(2x-14\right).\left(3^x-9\right)=0\)

Answer 1

\(\left(2x-14\right)\left(3^x-9\right)=0\)

=> \(\begin{cases}2x-14=0\\3^x-9=0\end{cases}\) => \(\begin{cases}2x=14\\3^x=9\end{cases}\) => \(\begin{cases}x=7\\3^x=3^2\end{cases}\) => \(\begin{cases}x=7\\x=2\end{cases}\)

Answer 2

\(\left(2x-14\right)\left(3^x-9\right)=0\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}2x-14=0\\3^x-9=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}2x=14\\3^x=9\end{array}\right.\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}x=7\\x=2\end{array}\right.\)