a) a) |-27|-|x-11|=3^18: (3^15 . 4 +5.3^15)
=> 27 -|x-11|=3^18: [3^15. (4+5)]
=> 27 -|x-11|=3^18: [3^15.9]
=> 27 -|x-11|=3^18: 3^15 : 9
=> 27 -|x-11|=27 : 9;
=> 27 -|x-11|=3;
<=> -|x-11|=3-27=-24;
<=> |x-11| = 24;
<=> \(\left[ \begin{array}{l}x-11 = 24\\x-11 = -24\end{array} \right.\)
<=> \(\left[ \begin{array}{l}x=35\\x=-13\end{array} \right.\)
.
b) (x-3). (x-5) < 0
TH1: \(\left[ \begin{array}{l}x-3< 0\\x-5>0\end{array} \right.\)
<=> \(\left[ \begin{array}{l}x<3\\x>5\end{array} \right.\)
KHÔNG CÓ Gía trị x NÀO THỎA MÃN
th2 \(\left[ \begin{array}{l}x-3> 0\\x-5<0\end{array} \right.\)
<=> \(\left[ \begin{array}{l}x>3\\x<5\end{array} \right.\)
=> 3 < x< 5
