a, 8.(12+35)-12.(8-35)
= 8.12 + 8.35 - 12.8 + 12.35
= 8.35 + 12.35
= 35.(8+12)
= 35.20
= 700
b, |x-2|=5
=> \(\left[ \begin{array}{l}x-2=5\\x-2=-5\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=7\\x=-3\end{array} \right.\)
Vậy x ∈ {-3;7}
c, 2-7.x=-47
=> 7x = 2 - (-47)
=> 7x = 49
=> x = 7
Vậy x = 7
d, |4x-12|=8
=> \(\left[ \begin{array}{l}4x-12=8\\4x-12=-8\end{array} \right.\)
=> \(\left[ \begin{array}{l}4x=20\\4x=4\end{array} \right.\)
=> \(\left[ \begin{array}{l}x=5\\x=1\end{array} \right.\)
Vậy x ∈ {1;5}
