a,|x+2|=0
⇔x+2=0
⇔x=0
b,128-3(x+4)=23
⇔3(x+4)=105
⇔x+4=35
⇔x=31
c, [(6x - 39) : 7 ] . 4 =12
⇔(6x-39):7=3
⇔6x-39=21
⇔6x=60
⇔x=10
d, ( x : 3 - 4 ) . 5 = 15
⇔x:3-4=3
⇔x:3=7
⇔x=21
e, ( 7 - x ) - ( 25 + 7 ) = -25
⇔(7-x )-32=-25
⇔7-x=7
⇔x=0
g, ( 3x - $2^{4}$ ) . 7³ = 2.$7^{4}$
⇔(3x-16).343=2.2401
⇔(3x-16).343=4802
⇔3x-16=14
⇔3x=30
⇔x=10
h, x - [ 42 +( -28 ) ] = -8
⇔x-14=-8
⇔x=6
i,|x-3| = |5| + |-7|
⇔|x-3|=12
⇔\(\left[ \begin{array}{l}x-3=12\\x-3=-12\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=15\\x=-9\end{array} \right.\)
k, 4 - ( 7-x ) = x - ( 13 - 4 )
⇔4-7+x=x-9
⇔-3+x=-9+x
⇔ x∈∅ ( x thuộc rỗng)
~ học tốt ~