8.(12+35)-12.(8-35) |x-2|=5 2-7.x=-47 |4.x-12|=8

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}